absorber for solar power

Absorber for Solar Power

W. Richard Powell

A simple, economical absorber utilizing a new principle of operation to achieve very low reradiation losseswhile generating temperatures limited by material properties of quartz is described. Its performance isanalyzed and indicates approximately 90% thermal efficiency and 73% conversion efficiency for an earthbased unit with moderately concentrated (tenfold) sunlight incident. It is consequently compatible withthe most economic of concentrator mirrors (stamped) or mirrors deployable in space. Space applicationsare particularly attractive, as temperatures significantly below 300 K are possible and permit even higherconversion efficiency.

1. Introduction

Solar energy can be converted into power directlyas in a photocell or indirectly with the absorber'sthermal output converted into power in a thermal en-gine. This work is concerned only with the absorberof an indirect converter; but to give adequate empha-sis on high temperature output, a Carnot engine effi-ciency factor will be included. Likewise, little will besaid of the concentrator optics, but for clarity a para-boloid mirror will be assumed.

In order for the absorber to be efficient, it must beblack to sunlight; yet if it is very hot for good Carnotefficiency, much of the absorbed radiation may bereradiated and lost. This dilemma has led others,1' 2

to utilize selective surfaces which for sunlight absorbwell, a 1, and for long wavelength radiation emitpoorly, e << 1, where a and e are absorption coeffi-cients. At present, surfaces with ale 10 for servicebelow 5000C can be fabricated. In contrast, the vir-tual surface or entrance hole of the absorber de-scribed in the next section exhibits an effective ale >

500 while producing exhaust temperatures in excessof 10000C. This is made possible by combining oldideas into a new principle of operation-the parts ofthe absorber that can radiate the long wavelength ra-diation well are kept cool by transfering the heat theyabsorb to a coolant flow, which is heated further toform the high temperature exhaust. The thermal ra-diation from the hot parts of the absorber is prevent-ed from reaching the entrance and escaping by eco-nomical selective surfaces and favorable geometricfactors. In concept, the device is much like a set of

The author is with Johns Hopkins University, Applied PhysicsLaboratory, Silver Spring, Maryland 20910.

Received 25 February 1974.

nested porous greenhouses with air flowing inwardthrough them to keep the outermost greenhouse cooland to remove heat from the innermost greenhouse.

11. Tubular Absorber

A. Description

Consider a long, thin walled glass tube open at oneend and sealed with a black cap at the other as shownin Fig. 1. The outer surface of this tube is coatedwith a highly reflecting silver film. A second slightlylonger cylinder surrounds this mirror tube, leaving anannulus between, which is sealed at both ends exceptfor an entrance pipe at the open end of the inner tubeand an exit pipe at the closed end to form a coolingjacket for the inner tube. Surrounding this secondcylinder is a layer of high temperature insulation-i.e., an evacuated annulus containing many separatedcoaxial layers of reflecting metal foils, the innermostbeing the shortest and covering only the end of theinner tube most remote from the entrance and pro-gressing in length to the outermost, which extendsthe full length of the absorber. Except for this detailmade necessary by an axial temperature gradient aswell as a radial one, this radiation shield is of conven-tional design and construction.

Now imagine that the closed end of this tubular as-sembly is pointed at the sun, while the open entranceof the central mirror tube encompasses the image ofthe sun formed by alarge paraboloid mirror, and thata cooling gas flows in the cooling jacket to preventthe mirror tube from melting. Since, as shown inFig. 1, the average solar photon reflects on the mirrortube walls many times before being converted intoheat, the thermal flux incident on the walls of theinner tube is much less intense than the flux acrossthe entrance. If the tubular assembly is long enoughfor most of the solar photons to be absorbed before

2430 APPLIED OPTICS / Vol. 13, No. 10 / October 1974

EXHAUST(HOT FLUID)

COOLANTENTRANCE

INSULATION FORHIGH TEMPERATURE(METAL FOILS INVACUUM SEPARATEDBY OXIDE DUST)

VACUUMWALL

SILVER FILMON GLASS TUBE

Fig. 1. Cross section of the tubular absorber, illustrating the mul-tiple reflections of a typical solar photon's path, s, and the typical-ly nonreflecting paths, t, of thermal radiation from one point of thewall near the hot end. Optical system concentrating sunlight on

open end is not shown.

striking the black end cap, then almost all of thesolar radiation will be absorbed, a 1; and the hotgas emerging from the exit pipe of the cooling jacketwill be approximately at the same temperature as theclosed end of the inner tube, which will be filled withessentially blackbody radiation characteristic of thistemperature, designated TL. In practical use a tubelength to diameter ratio of 15 is adequate.

Even with much lower reradiation losses from thevolume near the entrance due to the lower tempera-tures with coolant flow and the strong T4 tempera-ture law for radiation, much of the entering solarpower would escape again as thermal radiation if itwere not for the wavelength selective properties ofthe mirror tube walls. Only a small fraction of theintense blackbody radiation filling the end of thetube remote from the entrance 'can escape directly,and much of that directly escaping flux would be re-flected back by the shadowed or central section of theconcentrating mirror. For most of the radiation gen-erated by walls at temperature TL or less, the glasswalls are opaque, and consequently the intense wallradiation at the far end of the tube cannot see the sil-ver film and mirror its way out like the solar radia-tion did on its way in. (Glass is opaque to infraredradiation because it is an absorber not because it re-flects it.3) In this respect the tubular device resem-

bles a set of nested greenhouses except that solar re-flection at the glass greenhouse surfaces reduces thetransmission to the innermost greenhouse and thuslimits the number of greenhouses that can be usefullynested to three, whereas solar reflection by the glasssurface in the tubular device actually increases thetransmission of solar energy to the end remote fromthe entrance. In the interest of higher Carnot effi-ciency (higher TL) quartz may replace glass at thehot end of the mirror tube, but it should grade intoglass or be doped with an infrared absorber near thecooler entrance end to preserve this selective mirroraction. Thus while thin glass walls are desirable ifheat is transferred through them, they should none-theless be thick enough to be opaque to the wall ra-diation.

This tubular absorber can be significantly im-proved by refinements suggested in Sec. II.B, butthen the analysis required to predict its performanceis made much more difficult and will not be present-ed here, as even this inferior version will be shown tobe quite attractive. Environmental radiation enter-ing along with the sunlight will be neglected in theanalysis, but it also aids the system.

B. Refinements

(1) All the energy added to the gas flowing in thecoolant jacket must pass through the walls of themirror tube, and even if they are thin, some ineffi-ciency results. Thus if the coolant gas is transparentto sunlight it is both more economical and more effi-cient to eliminate the cooling jacket annulus and sim-ply connect the coolant flow exit tube through a veryporous black end cap at the remote end of the mirrortube. In order to do this on earth for a gas otherthan air, one can simply enclose both the tubular de-vice and the paraboloid mirror in a thin, pressuresupported, transparent plastic bubble. Even for airthis may be economically attractive to protect theconcentrating mirror and to remove wind loads fromthe heliotrope. In space applications the entrancesealing bubble need not enclose the concentratingmirror but is simply a pressure window remoteenough from the entrance to tolerate the pressureload with the partially concentrated solar flux inci-dent, perhaps including a fluxtrap4 as part of its sup-port structure as space mirrors are of low quality.Thus far we have tacitly assumed that the gas insidethe mirror tube is transparent for both the solar andheat radiation; however, many molecular gases, i.e.,water vapor laden air have strong absorption bandsin the infrared. Consequently much of the wall ra-diation that would otherwise escape can be internallyreabsorbed in the coolant flow. Not only does thiseffectively prevent wall radiation from escaping, butat high temperatures it significantly aids in the radialtransport of energy in the cooling gas and reduces ra-dial temperature gradients. Unfortunately the ra-diation from the hot gas partially replaces the wallradiation it prevents. But at no wavelength can thishot gas radiation exceed the essentially blackbody ra-

October 1974 / Vol. 13, No. 10 / APPLIED OPTICS 2431

diation it replaces; thus the net effect is beneficial.Because the hot gas radiates strong lines of bandsthat the cold gas does not absorb well, this calcula-tion of radiative transport inside the tube is verycomplex. Therefore in our analysis we have assumedthat there is a vacuum in the interior of the mirrortube and that coolant flow in the annulus is em-ployed.

(2) With uniform solar reflectivity the thermal fluxon the mirror tube walls decreases with distance fromthe entrance. Because of this and the fact that thecoolant temperature is steadily increasing, the heatflux into the coolant decreases with distance morerapidly than the thermal flux on the walls. Econom-ic considerations related to the insulation cost, maymake an intentional reduction in the solar reflectivitywith distance from the entrance desirable eventhough the reradiation losses would increase. Thenshorter tube lengths with the same net solar absorp-tion would be possible.

(3) Also the cross section of the mirror tube shouldincrease with distance from the entrance in the initialsection of the tube so that solar radiation collected bythe surface of the paraboloid mirror near the rim isconverted into more nearly paraxial rays after itsfirst reflection inside the tube and thus travels muchfurther into the tube before being absorbed. Theparaboloidotoroidal phocon5 is useful for this pur-pose. For example, if the rim angle of the concen-trating mirror is 600 the length of this initial phoconsection required to convert all rays to 30° or less in-clination to the tube axis is only 1.15 maintube diam-eters. The entrance area for this example would beonly 28% of the maintube cross section and conse-quently much of the shortest wavelength wall radia-tion or hot gas radiation not blocked by the selectivemirror action of the walls would fail to escape fromthis convergent phocon exit. Both the increased dis-tance between reflections for the solar radiation pro-pagating into the tube and the relatively larger maintube diameter also act to make the thermal wall fluxload very much smaller than the entrance flux.However, this paraboloidotoroidal phocon entrancesection increases the complexity of the analysis andlike the other improvements will be omitted.

C. Analysis

Since we assume that the absorber tube is perfectlyinsulated, the total energy transport rate across eachcross section is a constant. This net power absorbed

sorption. We will neglect K(x) since the thermalconductivity of the mirror walls is low (essentially thesame as glass), and as it increases only linearly withtube diameter, the total cross-section area of thewalls and coolant flow jacket can be made insignifi-cant compared to the tube area. From Eq. (6) ofRef. 6 we find the net wall radiation is

f5(x) = ATo 4 b(X) + BT(x) 3T'(x), (2)

where

A (7TD2/4)o,

B (47ToD3)(2 - E)/3E,

(3a)

(3b)

To -- T(0), (3c)

and the a is the Stefan-Boltzmann constant, D is themirror tube diameter, T(x) is the wall temperature, eis the wall emissivity at long wavelengths, and -rb(X)is the transmission efficiency of the tube for longwavelength blackbody radiation, which can be calcu-lated by the procedure described in Ref. 7. It is alsoconvenient to describe the other radiant fluxes interms of transmission factors, 7-(x) and r(x).

Thus,

FS(x) = FOTS(X),

fr(x) = Pfn(O)Tr(X)

= P Tr(x)[ATo4 + BTO3 T' (0)]

(4)

(5a)

(5b)

where

F0 F(O)

0 ' 1,

(6a)

(6b)

and

Tr(X) Tb(X), (7)

as the reflected radiation wavelength distribution isalmost identical with the wall radiation and the an-gular distribution is nearly blackbody in most designsof interest if p - 1. If p - 0, then the accuracy ofEq. (7) is of little concern. Also we shall assume'thatthe product of the coolant mass flow rate and thecoolant specific heat capacity, Cm, is constant as ifthe coolant were an ideal gas. If we also neglect radi-al temperature gradients, i.e., assume thin walls, then

P = C(x) - K(x) -f(x) + F(x) + f(x), (1)

where x is the distance from the entrance, C(x) is theconvective energy rate, K(x) is the power transported,back toward the entrance by thermal conduction,fn(x) is the net wall radiation traveling back towardthe entrance, FW(x) and fr(x) are, respectively, theshort wavelength radiation from the sun and the longwavelength radiation, escaping from the tube but re-flected back into it, which reach x without prior ab-

C (x) = CmT(x)

= F(T/TO)S- 1 ,

(8a)

(8b)

where S is the ratio of the primary radiation inputpower to thermal power input, CmT0. Now evaluat-ing Eq. (1) at x = 0 we find,

P - CmT = F - (1 -p)TO3 [AT + BT'(0)](9a)

= E Fo,


(9b)

where EaFo is the net radiant power captured by theabsorber tube and Ea is absorber efficiency. Thus atx = 0,

BTO3T'(0) = FO(1 - E.)/(l - p) - ATo4 , (lOa)

or, in general,

BTO3 T' = Cm(T - To) + Fo(Ts - Ea) + GTb,

(lob)

where

G pF0(l - Ea)/(l - p) - ATo4. (lOc)

Thus in dimensionless variables

d(T/To) 3 R 4 r(T/T0 ) - 1d(x/D) 16(2 - E) L S

(P 1 PE.)+ Tb ( 1p R4 -P )where

F0 = A(RTO)4

- Ea

+ T] ,

(llb)

and RTo is the temperature that a black disk cov-ering the entrance would attain in the cold radiationfield of space. Now R, f, p, and To are independentparameters, but Ea is dependent on them and S. i.e.,

Ea is a monotonically increasing function of Cm.

Unfortunately, Ea(R, s, p, To, S) is not known a prio-

ri. When Cm is large (S small), the temperatureachieved deep in the tube, TL, (L >> D) is low.

Hence, even though E0 is large when Cm is large, the

over-all efficiency

(12)E EE,

functions of Cm (or S) assuming that the parametersR. e, p, and To are fixed.

In order to find the monotonic function, Ea(Cm),

and consequently TL(Cm) or TL(S) via Eqs. (14) andthen E(Cm) or E(S) via Eqs. (15), we first character-ize the system under study by a set of values for theparameters of Eq. (11), and also for both p, the wall

reflectivity for the incident short wavelength flux,and f(O), its angular distribution, so that r,(x) can becalculated as outlined in Ref. 7. Then we select a

particular Ea of interest, calculate G, and guess a testvalue of Cm that we shall designate CT. If CT > Cm,

then as Eq. (11) is solved for T(x) at increasing x,using the initial conditions, the derivative T'(x) willremain too large for x 2 0 and in fact TL - o. Like-wise, if CT < Cm, then TL -- -as x - O. Conse-quently, for each physically realistic Ea there is aunique value of CT for which TL remains finite as x -o and the relationship between Ea and Cm or S is

found from this condition.But, for a simplified but practical example of this

procedure, we assume

Tr(x) = exp(-sx/D) (16a)

rather than calculate r(x) for some particular butequally arbitrarily chosen f(O). An inspection of Fig.2 of Ref. 7 will show that this functional form is a re-

alistic and conservative approximation for many f(O)

of practical interest if p 0.95 and 0 S 45°. Likewisefor simplicity in the illustration of this method wetake

Tb(X) = exp(-bx/D) (16b)

as a reasonable facsimile of a very complex function.Then differentiating Eq. (lOb),

BTO3T" = CmT' - (s/D)FOT, - (b/D)Gr,. (17)

is low because the thermal-to-mechanical power con-

version is limited by the Carnot efficiency

Ec = 1 - To/TL ,

where we have assumed To is also the Carnot exhaust

temperature as if the coolant were also circulatedthrough the Carnot engine as the working fluid.Since in Eq. (lOb), r Trb, and T' all approach zero as x

-I co

Ea = Cm(TL - T)FO -

or in terms of S

(TL/TO) = 1 + SEa,

and consequently,

E = Cm(TL - To)2(TLFo) 1,

(14a)

0t~

V)

(14b)

(15a)

or in terms of S

E = SEa2(TO/TL); (15b)

however, TL and consequently E are also unknown

I /I' I I I .I I I0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.

ABSORBER EFFICIENCY, Ea

>C.)z0

wz0

z

0C.,

Fig. 2. Ratio of solar to thermal input powers, S, Conversion effi-

ciency, E, and input to output temperature ratio TL/To vs Ea the

absorber thermal efficiency for a solar flux incident that would

heat a black disk insulated on back side to twice (R = 2) the cool-

ant entrance temperature, To.


(13)

If T"(O) 0, then Cm is too large as with uniformsolar reflectivity, the rate of temperature increasemust decrease with length. Thus evaluating Eq. (17)at x 0,

Cm Fo(l- Ea)/(1 p) -AT 4 1L ~BT03 J< (sF + bG)D-' (18a)

or

S '[ 3 ]

x (18)+ (1 Ea)/(1 p)Ls bp ( - Ea,)/( - 4-bR I 18b

Often the true value of Cm (or ) differs from theequality value given by Eqs. (18) by only a few per-cent. We will avoid numerical analysis here and con-tinue by using the largest value of Cm permitted byEqs. (18), i.e., the equality value. This approxima-tion is conservative, as the value of TL calculatedfrom Eqs. (14) for fixed values of all the parameterson the right side of Eqs. (18), including Ea, is a fewpercent too low. Thus the Carnot efficiency andconsequently the over-all efficiency E calculated withEqs. (15) is underestimated by a few percent if Cm istaken at the largest value permitted by Eq. (18).

Now with reference to Fig. 2 of Ref. 7, we assume

s = 0.05 (1 Q')and

b = 0.5

\(19b

(I 9b)

D. Comparison

A conventional black absorber-radiator in thesame solar flux would have much greater reradiationlosses, lower Ea, and reach temperatures far less thanTL. For example, a conventional black absorber inan R = 2 flux has a peak temperature even with nouseful power output of only 2TO, thus its Carnot effi-ciency would not exceed 50% even if the over-all effi-ciency fell to zero. Thus this tubular device is threeto four times more efficient and functions well inpoorly concentrated sunlight.

We can define an effective emissivity, e, for the en-trance surface in terms of the exhaust temperatureachieved and the reradiation losses, i.e.,

F0(1 - Ea) eATL4

and a = 1, as we have already noted. Thus,

a/e = (TL/RTo)4(1 -EJ -',

or in terms of the dimensionless variablesmodel,

(20)

(2la)

of our

a/e = [(1 + SEa)/R]4 ( - Ea)'. (21b)This effective ale at optimum coolant flow rate isalso shown in Fig. 3. In general this merit indexshows that this approach is much superior.

E. Discussion

This analysis has assumed that the absorber wasdeployed in the cold radiation field of space. Be-cause of its high efficiency, relatively little waste heatmust be rejected. Thus, in space, with a relativelysmall waste heat radiator located in the shadow of

as plausible values for the attenuation coefficients ofshort and long wavelength radiations propagating inthe tube. Also from Ref. 3 we take

E = 0.9

1o5

(19c)

and assume

p = 0.5 (19d)

as a conservative estimate of the fraction of wall ra-diation that can be reflected back into the tube witha good optical design-phocon or external mirrors.Next, for a particular R, i.e., R = 2, we assume vari-ous values for E and with Eq. (18) calculate the cor-responding value of S and then for this S and E cal-culate E from Eq. (15b). The results of this R = 2case are shown in Fig. 2, and we see that a maximum,over-all efficiency of 73% results when E = 90%.More rapid coolant flow would produce higher ab-sorber efficiency but lowers the exit temperature ex-cessively. Likewise less rapid coolant flow can resultin better Carnot efficiency, but reradiation losses re-duce E excessively. The efficiency at optimumcoolant flow rate for other values of R is shown in Fig.

x 1040

I-

If

w

z0C LLJ

z

0C.

2 3 4'

SOLAR FLUX INDEX, R

Fig. 3. Conversion efficiency, E, and effective ale merit index atoptimum coolant flow vs solar flux index, R, ratio of a one-sidedblack disk absorber temperature to coolant entrance temperature.


I I

the concentrating mirror, To << 300 K would be pos-sible. Then rather large values of TL/TO could betolerated without damage to a quartz mirror tube.In addition to higher predicted efficiency, for unitsproducing several kilowatts or more, this absorberand advanced turbine generators4 8 developed forspace applications offer significantly lower cost andliftoff weights compared with either solar cells or iso-topic power supplies.

On earth, To 2 300 K, and material problems limitthe TL/To ratio to about 5. Thus for most of the day,even in northern latitudes, the flow rate would be au-tomatically controlled to maintain the highest possi-ble Carnot efficiency permitted by the constructionmaterials and the absorber would operate at greaterthan optimum efficiency. A linear slot absorber overa parabolic mirror is also attractive and may also beable to produce a materials limited exhaust tempera-ture.

In spite of the fact that Ea is nearly unity, econom-ic considerations would result in a significant part ofthe sunlight collected by the concentrator beingpoorly focused and wasted. However, unlike the un-collected waste heat that goes up the chimney of aconventional power plant and adds to the local envi-ronmental heat load, this concentrated sunlight canbe reflected so as to escape from the earth at negligi-ble incremental cost. Thus there need be no changein the local albedo. Since this simple economic ab-sorber is not dangerous, does not require intense sun-light, and need not have any net local ecological im-pact, it should be located in urban power demandareas to avoid transmission losses. It can also make

fuel by producing hot steam for a chemical crackingprocess. 9

11. Summary

A high temperature solar absorber utilizing newoperating principles to reduce reradiation losses hasbeen described. One, less than optimum, examplehas been analyzed, neglecting both thermal conduc-tion losses and environmental radiation gains, usingexpressions for r, and Tb that are simplified mathe-matically but physically quite plausible. High effi-ciency is predicted even with poorly concentratedsunlight such as would be available from a flexiblemirror deployed in space or from concentration op-tics economically deployed on earth. Ironically ale<< 1 for the mirror-tube walls permits fantasticallyhigh effective ale ratios for the tubular absorber.

References

1. A. B. Meinel and M. P. Meinel, Phys. Today 25, (2), 44 (1972).

2. B. 0. Seraphin, Appl. Opt. 12, 349 (1973).3. R. Gordon, J. Am. Ceram. Soc. 44, 305 (1961).4. K. E. Nichols, Progress in Astronautics and Aeronautics (Aca-

demic Press, New York, 1963), Vol. 11, p. 891.5. V. K. Baranov, Geliotekh. 2, (3), 11 (1966).6. W. R. Powell, Appl. Opt. 13, 593 (1974).7. W. R. Powell, Appl. Opt. 13, 952 (1974).8. D. A. Perz, 7th Intersociety Energy Conversion Engineering

Conference (American Chemical Society, Washington, D.C.,

1972), p. 346.9. Euratom CCR-ISPRA, Report 1, "Hydrogen Production from

Water Using Nuclear Heat" (1972) Available from NTIS (EUR-4776e).

Berge Tatian (Itek), Roland Shack (University of Arizona), and fellow opticists photographed in October 1972 by J. Zimmerman (Itek).


Books continued from page A18ed the ether drift experiment (again with negative results) andbegan to measure the velocity of light in a vacuum. This work wasnearly completed when Michelson died in May 1931.

Mrs. Livingston spent ten years researching this book. She de-scribes it as a "quest for my father." She interviewed numerousscientists, many of whom knew her father. Her text was reviewedby a number of experts. One gains the impression that she pre-pared this book much as her father undertook optical experiments,and as her father's research has contributed to our understandingof optics, so her efforts contribute to our perspective of an erawhen so many advances were being made in optics.

D. J. LOVELL

The Raman Effect, Volume 1: Principles; Volume 2: Ap-plications. By A. ANDERSON, Editor. Dekker, New York,1971 and 1973. 404 pp. and 629 pp. $29.75 and $45.

The companion volumes of the set, The Raman Effect, Volume1: Principles and Volume 2: Applications, represent a series ofeleven eclectic articles designed to survey the basic experimentaland theoretical procedures of Raman spectroscopy and to describein moderate depth the relevance of this light scattering techniqueto various areas of chemistry and physics. Although the volumesare nominally divided into principles (Vol. 1 has six chapters) andapplications (Vol. 2 has 5 chapters), a strict separation is fortu-nately not achieved. The inevitable duplication that naturallyarises between the various contributions does not detract from theover-all scope of the two volumes, as might be expected but actual-ly adds to the readability of the individual articles. I personallyhave been browsing through both volumes for several months andhave been repeatedly impressed by the exceptional clarity andpointedness of the presentations, attributes that carry over even tothose sections that are necessarily more comprehensive in theirtreatment.

Volume 1 begins with a Historical Introduction by R. S.Krishnan that acquaints the reader briefly with the progress ofRaman spectroscopy within roughly three time periods: 1928-1940, 1940-1960, and 1960 to about 1970. G. W. Chantry followswith a discussion on the polarizability theory of the Raman effect.After introducing both the classical and quantum mechanical view-points of Raman scattering, the author directs the discussion to-ward the Wolkenstein bond polarizability model and the impor-tance of absolute intensity measurements in furthering our under-standing of bond properties.

The subject of Raman scattering in crystals is heavily empha-sized in this series of books. The chapter in Volume 1 by R. A.Crowley concerning the Theory of Raman Scattering from Crys-tals will appeal primarily to the reader with a strong physical in-terest and background. Volume 2 contains two further contribu-tions related to crystal studies: (1) Raman Spectra of MolecularCrystals by R. Savoie, and (2) Raman Spectra of Ionic, Covalent,and Metallic Crystals by G. R. Wilkinson. Savoie's chapter is ofrelatively narrow scope and stresses analyses of spectra of smallcondensed phase molecular systems as, for example, HC1, HCN,and CF4. In contrast, Wilkinson's article is comprehensive andcontains innumerable examples of the more recent Raman litera-ture (from about 1960 to 1971). Short discussions concerning boththe theory of vibrational spectra of solids and the various experi-mental factors involved in crystal studies introduce Wilkinson'schapter. The bulk of the discussion, approximately 100 pages,deals with Raman spectra of crystals of the elements (metal andnonmetal) and crystals with AB, and AXBVCZ compositions.Short sections are presented on scattering in mixed crystals and onother scattering effects, as, for example, resonance Raman effectsand scattering from magnons and plasmons. A useful crystal

index follows the chapter. [For investigators particularly inter-ested in the structure and dynamics of solids, further detailed dis-cussions of one-phonon processes, which amplify sections ofSavoie's and Wilkinson's chapter, can be found in the relativelynew book Infrared and Raman Spectra of Crystals by G. Turrell(Academic Press, 1972).]

Also in Vol. 1, C. E. Hathaway deals thoroughly with the di-verse subject of instrumentation in the chapter: Raman Instru-mentation and Techniques. This contribution will be of morethan passing interest to newcomers to Raman procedures, as wellas those investigators concerned with general design modificationsand component construction. Two final chapters, The StimulatedRaman Effect by P. Lallemand and Brillouin Scattering by R. S.Krishnan, complete the volume on Principles.

Volume 2 begins with a lengthy contribution on Applications toInorganic Chemistry by R. S. Tobias. In addition to an encyclo-pedic list of references, the author includes an extremely usefulcompound index. The chapter examines various sample handlingdetails and describes several of the more specialized sample cellsoften required in inorganic studies, as, for example, high tempera-ture cells or cells utilized in examining acidic fluoride prepara-tions. A short, but useful, discussion follows on intensity mea-surements and the procedures required both for quantitative workand for calculating elements of the derived polarizability tensor.Next, the author presents material concerning the Raman spectraof a variety of small molecules, ionic species, oxyanions, metal ha-lide complexes, metal amines, the ever popular metal carbonyls,cyanide complexes, and organometallic compounds. Sections thenfollow on aqueous and nonaqueous solution studies and on the useof Raman spectroscopy for determining equilibrium constants. Afinal excursion into the spectroscopy of molten salt solutions com-pletes the selection.

J. A. Koningstein and 0. S. Mortensen present a brief discus-sion of what are primarily their studies of the trivalent rare earthions in the chapter: Electronic Raman Transitions. These transi-tions are distinguished by the appearance of asymmetric scatteringtensors in contrast to the symmetric tensors usually found for rota-tional and vibrational transitions.

The chapter by A. Weber on High Resolution Raman Studies ofGases is clearly an outstanding effort that could stand alone as amonograph on the subject of the structure and dynamics of gas-phase systems. The author first concisely reviews the generaltheory of rotational Raman scattering. A discussion of the experi-mental details for obtaining high resolution spectra follows with abrief summary of prelaser techniques. Descriptions of optical sys-tems built around laser illumination are then presented, and somediscussion is devoted to interferometric methods. The authorthen critically reviews the results from primarily the rotation spec-tra of about forty individual molecular systems. Since structuralparameters are ultimately derived from rotation constants, a care-ful distinction is made between the classes of structural data oneobtains spectroscopically; that is, the differences between re (equi-librium) structures, r and r (average) structures, and rg (electrondiffraction) structures. A table is presented that tabulates r.structures from Raman spectroscopy and compares them with rgelectron diffraction values where possible. Discussions of the Co-riolis and centrifugal distortion dynamical parameters are also in-cluded. The chapter concludes with a brief, but concise, sectionon the important subjects of intensities, line widths, and lineshifts.

Although Vol. 2 has only recently become available, the readershould remember that the references include material, in general,to about 1970. This is not an adverse criticism, as the aim of theseries was not meant to be a current, annual review effort. De-pending upon one's specific interests, a reader may be stronglymoved to comment on subjects glossed over or areas neglected. Iwish at this point to make only one comment along these lines andthat is to note again the phenomenal speed with which areas of


Raman spectroscopy literally burgeon and flourish. Perhaps if the

editor were to commission authors today, rather than several yearsago, he would undoubtedly have included for Vol. 2 a chapter, or

chapters, dealing with aspects of Raman spectroscopy of either bi-

ological or polymeric systems. A case may be made that a third

volume in the series should be devoted to these general disciplines.

In summary, these two volumes present a highly competent,

lucid survey of a variety of intrinsically exciting areas involving

Raman spectroscopy. Unfortunately, the high price placed by the

publisher on these individual volumes will undoubtedly decrease

the accessibility of the books to those students and investigatorswho would most likely profit from an acquaintance with this versa-

tile technique.

IRA W. LEVIN

Remote Sensing in the Troposphere. V. E. DERR, Editor.U.S. Government Printing Office, Washington, D.C., 1972. 852

pp. $9.00.

Writing a textbook is an extremely difficult task. One must

combine a thorough knowledge of the subject with an intuition re-

garding the problems a student may meet in grasping the material.The material must be organized in a logical sequence to present

the necessary information. The effort is compounded if the text iswritten on a subject in which current research is developing new

information. And the presentation becomes nearly impossible if

the text is to be authored by 30 scientists.The book reviewed here was compiled by 30 authors as a text for

a course on remote sensing of the troposphere given at the Univer-

sity of Colorado in the summer of 1972. This course was jointly

sponsored by the University of Colorado and the National Oceanicand Atmospheric Administration.

Despite the qualms expressed in the preceding paragraph, one

should not jump to the conclusion that this book is lacking invalue. On the contrary, the 30 chapters (nearly 1000 pages) pre-

sent a considerable amount of information. Unfortunately, too

much of it tends to be pedantic; and the material lacks cohesion.Several fundamental formulas are derived, but it is not clear why

this is done. On the other hand, some chapters make for delight-

ful reading. For instance, Freeman F. Hall, Jr., describes the usesof acoustic echo-sounding techniques to determine the tempera-ture and wind structure of the atmosphere with an adequete theo-retical basis; he also provides an interesting description of the ex-

perimental results and their significance. Similarly, Harold Yatesgives a clear and meaningful account of the information being de-

rived by both optical and microwave sensors carried in satellites.

The coverage is extensive. The first seven chapters are con-

cerned with the lower atmosphere. The next four chapters dealwith wave propagations and their interactions. Then, 15 chaptersdiscuss remote sensing. These chapters describe radar and Dop-pler radar techniques, radiometry, acoustic methods, lidar, satel-lite measurements, and acoustic-gravity apparatus. This sectioneven extends the coverage to the remote sensing of the ocean and

pollution monitoring. Special topics are covered in three chap-

ters, and a final chapter summarizes the status of remote sensingof the troposphere.

There is little doubt that this book contains much valuable in-

formation. My major criticism is that the book is too ambitious.Minor faults include the fact that symbols are uniform only withineach chapter and that a 20-page errata sheet is required to correcterrors. I must compliment the editor and authors for providing anextensive index and excellent bibliographies for each chapter.

D. J. LOVELL

Fourier-Optik und Holographie. By E. MENZEL, W. MIR-ANDE, und I. WEINGARTNER. Springer-Verlag, New York,1973. 358 pp. $75.90.

The past two decades have seen a renaissance in optics, and the

past few years have seen the publication of a number of books that

attempt to describe the innovations and, recently, to incorporatethem into the complex framework of traditional modern optics.In the early 1950s, Gabor published the papers from which the im-mense literature of holography sprang. In 1959, the first editionof Born and Wolf's Principles of Optics appeared, and this re-vealed to scientists who had not closely followed the specialist lit-erature the elegant structure of partial coherence theory and theconcept of transfer functions for optical instruments; in particular,it made self-evident the central role of the Fourier transform inthe theory of image formation.

The book under review belongs with a number of other volumes

that have appeared recently, of which Papoulis's Systems andTransforms with Applications in Optics is worthy of special men-tion in which the role of the Fourier transform is sin-gled out. Holography and image formation in general are then

seen to revolve around this mathematical device. This book con-tains chapters on interference and coherence, diffraction, imageformation with coherent illumination, two-wave interferencefields, spatial filtering, and the foundations and applications of ho-lography by Menzel; on spatial and chromatic partial coherence,on the transfer function of the recording medium, and on partiallycoherent holography by Weingartner; and on recording media forholograms by Mirand6. These are for the most part clearly writ-ten and well organized; the sections on spatial filtering and on therecording media are particularly lucid. Nevertheless it must besaid that although a very wide range of material is covered, it is for

the most part dealt with briefly; the reader reasonably could havehoped to find a more detailed treatment of some topics. Thesubject of electron holography, about which the authors have writ-ten several long articles, is a case in point. The literature of the

subject is well covered in the list of references.It has become so customary for reviewers to complain about the

prices of books that the impact is becoming blunted by repetition.

In this case, though, no reviewer should fail to animadvert againstthe price: nearly $76 for 358 pages-admittedly glossy. The text

has even been printed in East Germany, which used to be a way of

reducing production costs. At such a price, this review is the near-est that most potential readers, and even librarians, will get to acopy of the book.

P. W. HAWKES

Patents continued from page A26

tooptical deflectors. This patent is devoted to a detailed discussion of theadvantages. W.L. H.

3,661,442 9 May 1972 (Cl. 350-150)

Electrically operated optical shutter.A. KUMADA and M. KOGA. Assigned to Hitachi, Ltd. Filed 17Mar. 1970.

This important and interesting patent describes unusual electroopticalshutters using KDP or gadolinium molybdate in a ferroelectric. mode withhysteresis so that one electrical pulse opens the shutter and another closesit. W.L.H.

3,682,532 8 Aug. 1972 (Cl. 350-157)

Optical system to reduce image to lens distance bypolarization control.W. E. MYLES. Assigned to The Singer Co. Filed 3 Feb. 1971.

Two semitransparent mirrors in line will allow a convergent beam of lightto be folded upon itself and thus allow the region of convergence to be short-ened but at the expense of multiple images. By polarizing the light, and in-troducing a quarter-wave plate between the two, the desired beam emergesorthogonal to the direct beam and can be selected out with a circular analyz-er. The idea is not new; what is patented here is its application to displaysused in training devices. W.L.H.


11 July 1972 (Cl. 350-157) 3,718.751Reflecting optical system capable of compensating for thevariation in polarization mode.T. YAMAMOTO and T. KASAI. Assigned to Nippon Kogaku K.K. Filed 23 Dec. 1970.

A beam of polarized light reflected at oblique incidence has ellipticity in-troduced. The inventors show that the ellipticity can be compensated byintroducing a half-wave plate and another reflection as shown in the figure.

W.L.H.

3,675,989

B2A

½Hl Hi.t

I

Optics for high sensitivity color television camera.J. K. LANDRE, D. D. KLINE, and M. W. BROEMMELSIEK.Assigned to Commercial Electronics, Inc. Filed 12 Oct. 1970.

The three inventors we meet here have discovered that trichroic filtersfrom OCLI are insensitive to the polarization of the incident light at 450 andhave patented their use in TV color cameras. What does OCLI say to that?

W.L.H.

3,719,415 6 Mar. 1973 (Cl. 350-157)Radial and tangential polarizers.E. G. RAWSON. Assigned to Bell Telephone Laboratories, Inc.Filed 22 Sept. 1971.

This puzzling patent reveals little of what the inventor had in mind. Hespeaks of graded-index glass fibers for use as waveguides and then suggeststhat they be sectioned at very small intervals so that polarizers can be in-serted, either radial or tangential. A series of similar polarizers will at-tenuate the skew rays, he says, while dissimilar ones will transmit the skewrays and attenuate the meridional. He can't be serious! W.L.H.

3,728,545 17 Apr. 1973 (Cl. 250-83.3 HP)Infrared imaging apparatus.I. R. ABEL. Assigned to Honeywell, Inc. Filed 28 Apr. 1971.

This patent describes a cleverly folded optical scanning system for in-frared imaging. W.L.H.

11 July 1972 (Cl. 350-160)Liquid crystal optical cell with selected energy scattering.R. PIETSCH and B. L. LEWIS. Assigned to Radiation, Inc.Filed 26 Nov. 1969.

The text of this patent discusses retroreflectors exclusively. The problemis to modulate the light at a retroreflector before returning it to the source.The method suggested is to use liquid crystals that scatter when subjectedto shear. Crystals with these properties are an article of commerce. Sur-prisingly, however, the claims that were granted are quite general and coverany modulator using liquid crystals in a shearing mode driven by an "elec-tromechanical transducer." W.L.H.

CURRE"T

resolution. ~ ~ ~ solm

6 g 6 74,5 S

W.~ ~ H. WATSON. Assine to ZeihRai 6op.Fld84Fb1972.~ ~ ~ ~~~~~63 12t

3,713,721 30 Jan. 1973 (Cl. 350-150)Polarized light beam scanning with improved angularresolution.W. H. WATSON. Assigned to Zenith Radio Corp. Filed 14 Feb.1972.

A beam of monochromatic light can be deflected by acoustic waves in acell or by switching its polarization and sending it through a Wollastonprism. This inventor does both. W.L.H.

3,718,078

3,729,253 24 Apr. 1973 (Cl. 350-175 GN)Optical system comprising a single element having acontinuously varying index of refraction.D. T. MOORE and P. J. SANDS. Assigned to Western ElectricCo., Inc. Filed 28 May 1971.

This beautiful patent first recapitulates the history of lenses with nonuni-form index of refraction and then breaks new ground, much already de-scribed in JOSA in 1970. Sands is a student and colleague of Hans Bu-chdahl whose high standards are sustained here. W.L.H.

27 Feb. 1973 (Cl. 95-49)Smoothly granulated optical surface and method for makingsame.W. T. PLUMMER. Assigned to Polaroid Corp. Filed 31 Dec.1970.

Translucent projection screens are more subtle than textbooks admit.Since you know where the light comes from (the projector), it can be direct-ed at the audience, if you knew where they are. A Fresnel lens is a goodstart, but if it is well made you get an image of the projector lens. Anyonesitting with his eye in that image will see a good picture, but no one else willsee anything. Ground glass solves this problem but wastes light because itscatters so much that some of the light actually turns around and goes back.What is needed is a way of putting low-angle ripples or dimples on thescreen to spread the light slightly but not waste it. This patent shows howthis can be done by spraying droplets of a solvent on a plastic Fresnel lens.As they dry, the plastic becomes irregular in a controlled way. It is to beused in a camera viewfinder, so slopes of 2 or 3 are enough to relax the tol-erance on locating the pupil of the eye. W.L.I.


3,675,986 . . 27 Feb. 1973 (Cl. 178-5.4 E)

3,734,619 22 May 1973 (Cl. 356-27)Method Utilizing Brewster angle for determining angularvelocity and light beam incidence angles.R. G. NEWBURGH. Assigned to U.S.A. as represented by theSecretary of the Air Force. Filed 10 Aug. 1971.

This profound idea will certainly be hard to reduce to practice. There is arelativistic change of Brewster's angle when the surface moves at velocity V,but the effect is only as V/C. The invention is to use the change in angle tomeasure the edge velocity of a rotating object. W.L.H.

e

/5

6

'3

3,792,916 19 Feb. 1974 (Cl. 350-163)Anti-laser optical filter assembly.D. S. SARNA. Assigned to The U.S.A. as represented by the Sec-retary of the Army. Filed 25 Feb. 1969.

A filter assembly is described for selectively removing preselected individ-ual emission lines of laser energy from the visible spectrum comprising atleast one pair of Fabry-Perot type filters which transmit laser energy emis-sions for dissipation in the filter assembly and reflect harmless radiation fortransmission through the assembly. A plurality of these filter assembliesparallelly juxtaposed are also used to provide a filter screen for protectionagainst laser energy emissions. The structural details shown are sketchy,and the suggested structure may be inadequate where powerful lasers areconcerned. J.J.J.S.

/0

28 " . -;~ -,16 14

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3234

22'32A ~248\

3,793,518

3,783,295 1 Jan. 1974 (Cl. 250-567)

Optical scanning system.D. H. CASLER. Assigned to International Business MachinesCorp. Filed 30 Sept. 1971.

A scanning system using infrared illumination views selected portions of adocument for character recognition purposes. If recognition fails, a second,visible, strobed source is switched on to provide a view of the doubtful char-acter to the operator through the same optics. J.J.J.S.

26

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19 Feb. 1974 (Cl. 250-83.3 H)Optical scanning system with a crossed scanning pattern.K. W. HARPER. Assigned to Ithaco, Inc. Filed 17 Mar. 1972.

An optical scanning system for horizon scanners and the like is described,which provides a dual-lobe crossed scanning pattern. A detector arrange-ment receiving radiation from the scanner provides sufficient signals for de-termining the attitude of a space vehicle with reference to a planet aboutwhich the space vehicle is orbiting. Considerable specific detail on opticalconstruction and circuitry is given. The claims are specific to the device de-scribed. J.J.J.S.


I

3,795,803 5 Mar. 1974 (Cl. 250-338 H)Radiant energy optical detector amplifier.B. ANCKER-JOHNSON. Assigned to The Boeing Co. Filed 21Sept. 1972.

A semiconductor device is described that can be biased to inhibit currentflow. Illumination of the cathode starts an impact ionization wave throughthe semiconductor which releases a greatly augmented current pulse whenthe wave reaches the anode. The claims are quite broad. No specific con-struction information is disclosed. J.J.J.S.

r16

3,796,479 12 Mar. 1974 (Cl. 350-150)Electro-optical light-modulation cell utilizing a nematogenicmaterial which exhibits the Kerr effect at isotropictemperatures.W. HELFRICH, M. SCHADT, and H. SCHERRER. Assigned toHoffmann-La Roche, Inc. Filed 11 July 1972.

An electroopticaf light-modulation cell having a dielectric disposed be-tween electrodes and being comprised of a nematogenic fluid in the isotropicstate, is described. Said dielectric, upon application of a voltage to the elec-trodes, becomes doubly refracting. Considerable operational detail is givenin the disclosure. The claims are drawn to the use of a nematogenic fluid inthe cell. J.J.J.S.

3,797,913 19 Mar. 1974 (Cl. 350-150)Electro-optic display device.T. MORI, C. KOJIMA, and H. TAMURA. Assigned to SonyCorp. Filed 29 Nov. 1971.

A display device is formed as a sandwich having embedded in the centrallayer typically a seven-bar configuration of electrodes. The electrode ele-ments have their angle of doubly refracted light altered if voltage energized.As a result, those elements that are energized-appear as a pattern against acontrasting background when externally illuminated. The claims are limit-ed to the particular combination disclosed. J.J.J.S.

4 & 28Xa9

-48 ~8

3,798,366 19 Mar. 1974 (Cl. 178-6.8)Infrared imaging system.R. P. HUNT and R. H. WINKLER. Filed 6 Mar. 1972.

This system patent describes in some detail circuit means for producingsimultaneously a picture of an object and a graph showing temperature levelalong an indicated element of the picture. The principal object of the sys-tem is to do all this in a single package. The circuitry is composed of con-ventional solid state elements. J.J.J.S.

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3,797,911 19 Mar. 1974 (Cl. 350-96 WG)Thin film optical couplers employing mode conversion.H. W. KOGELNIK and T. P. SOSNOWSKI. Assigned to BellTelephone Laboratories, Inc. Filed 10 Oct. 1972.

A coupling means for introducing a light beam into a thin film waveguideand conversely extracting it therefrom is described. The operation dependson the relative indices of refraction of the guide path and the substrate andthe orientation of the optic axis of the substrate. No practical informationfor construction of the coupler is given. J.J.J.S.

3,798,452 19 Mar. 1974 (Cl. 250-213 R)Image intensifiers.E. SPITZ, E. LEIBA, and G. ASSOULINE. Assigned to Thom-son-CSF. Filed 27 Oct. 1971.

A liquid crystal storage type image converter is used to receive an imageto be viewed or copied. Illumination from a white light source is then re-flected from the converter and imaged at the viewing place. After viewing iscomplete the image in the converter may be electrically erased. Descriptionof the invention is so full of typographical and grammatical errors that con-fusion is possible although the operation is quite obvious. Claims are limit-ed to the particular structure described. J.J.J.S.

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3,800,156 26 Mar. 1974 (Cl. 250-330)Infrared image converting device.T. KOHASHI and T. NAKAMURA. Assigned to MatsushitaElectric Industrial Co. Filed 1 June 1971. Continuation of Ser.No. 659,703, 10 Aug. 1967, abandoned.

An ir imaging device is made by generating visible light in an electrolumi-nescent layer and quenching parts of this luminous field with the ir beingimaged thus making the ir image visible. A number of possible dispositionsof the invention are described. J.J.J.S.

INFRARED IMAGE

27

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3,801,185 2 Apr. 1974 (Cl. 350-160 R)Switch for thin-film optics.V. RAMASWAMY and R. D. STANDLEY. Assigned to BellTelephone Laboratories, Inc. Filed 6 Dec. 1972.

The index of refraction of the material composing a thin film light guide israised by an electric field, thus causing light to be confined to the guide.When the field is shut off light is lost from the guide, giving the effect of anoptical switch. The specific device shown in the figure is claimed. J.J.J.S.

The Optical Society of America willsponsor a series of meetings on opticalfabrication and testing. The schedulefor the meetings is as follows:

November 8-9, 1974HARTFORD, CONN.

November 10-11, 1974ROCHESTER, NEW YORK

March 14-15, 1975SAN FRANCISCO, CALIF.

March 19-20, 1975LOS ANGELES, CALIF.

June 1975CHICAGO, ILL.DALLAS, TEXAS

Fall 1975PHILADELPHIA, PA.

These meetings are organized primar-ily for opticians, but will be of interestto optical shop engineers and techni-cal staff.

A group of traveling lecturers willspeak at each meeting. In addition,technical contributions will be ac-cepted from individuals working in thefield. Sessions will feature discussionof tools and materials, review of proc-esses, and analysis of future require-ments. Exhibits of materials and in-struments will be held at all of themeetings.For further information write to:

Optical Society of America2100 Penn. Ave. N.W.Washington, D. C.(202) 293-1420


OpticalFabricationand TestingMeetings

I

X \ X X27I I

AMERICAN VACUUM SOCIETY335 EAST 45 STREET, NEW YORK, NEW YORK 10017 * (212) 685-1940

American Vacuum Society Scholarships for Graduate Study, 1975-76

Applications are invited for American Vacuum Society scholarships for

the 1975-76 academic year. These scholarships are given for graduate work

in the area of science described in the American Vacuum Society charter,

including vacuum science and technology, vacuum metallurgy, surface physics

and thin film research.

Selection of recipients is based upon the student's academic record,

his need, his area of graduate research, and his major professor's recommen-

dations. The scholarships cover one academic year but may be renewed once

and only once if re-application is made. The scholarships carry a maximum

grant of $4000 each per academic year.

Competition for these scholarships is open to the general public.

Graduate work done at a school with a recognized reputation in the areas of

interest is favored. The recipient must not be a member of the American

Vacuum Society.

Application forms are now available for the AVS student scholarships

for the academic year 1975-76, Applications may be obtained by writing to:

American Vacuum Society, 335 East 45th Street, New York, N.Y. 10017. The

completed applications, together with all supporting material, must be

returned to the same address by 31 March 1975. The selections will be made

and the recipients informed by June 1975.


CALL FOR PAPERS

SIXTH INTERNATIONAL SYMPOSIUM ON

ACOUSTICAL HOLOGRAPHYAND IMAGING

February 4-7, 1975Catamaran Motor HotelSan Diego, California

Sponsored by Office of Naval Research

Hosted by Naval Undersea Center

In cooperation with Acoustical Society of America

and IEEE Group on Sonics and Ultrasonics.

PA P E RS are sought on new techniques, devices, and theories of acoustical holographyand imaging. The formal presentation will be 20 minutes with an ample period reserved for discussion.

A BST RACTS (original and 4 copies) of candidate papers should be submitted to theSymposium Chairman, Newell Booth, Code 6513, Naval Undersea Center, San Diego, CA 92132. Please

prepare them in the format described on the following pages.

P RO C E ED I N G S The authors of all papers accepted will be requested to provide

a copy of their manuscript at the time of the symposium for publication in the proceedings. Instructionswill be provided with the letter of acceptance. Plans are being made with Plenum Press for publicationas volume 6 of Acoustical Holography.


Medical X-RayPhoto-Optical

Systems EvaluationOCTOBER 21-23, 1974

Cross Keys Inn,Columbia, Maryland

A SYMPOSIUMPRESENTED BY

Bureau of Radiological HealthFood and Drug Administration

Department of Health, Education,and Welfare

IN COOPERATION WITHThe Society of Photo-Optical

Instrumentation Engineers

GENERAL CHAIRMAN: Roger H. Schneider, Director,Division of Electronic Products, Bureau of RadiologicalHealth, FDA.PROGRAM CHAIRMEN: Kenneth E. Weaver, Chief, Medi-cal Physics Section, Bureau of Radiological Health, FDA.Robert F. Wagner, Research Physicist, Bureau of Radiologi-cal Health, FDA. David J. Goodenough, Assistant Professor,The Johns Hopkins Medical Institutions.

The Bureau of Radiological Health, Food and DrugAdministration, conducts a national program to limithuman exposure to ionizing and nonionizing radia-tion. Under Public Law 90-602, the Radiation Con-trol for Health and Safety Act of 1968, the Food andDrug Administration develops criteria and regulatorystandards for limiting unnecessary radiation exposureand develops methods and techniques for controllingradiation exposure and maximizing the effectivenessof useful radiation exposure such as that delivered inthe practice of diagnostic medicine.One area of present concern is the effect of the per-formance of medical radiological imaging systems onthe quantity and quality of diagnostic informationand patient radiation dose. The Bureau of Radio-logical Health is presenting this conference to addressproblems in this area. The conference will consistof five sessions: Film-screen sensitometry, film-screenoptics, image intensifiers, x-ray tube focal spots, andnew developments in radiological imaging systems.The participants in each session will include physi-cians, physicists, and engineers working in that par-ticular specialty. Each session wil I consider questionsof diagnostic needs, the state-of-the-art of measure-ments, and possible conventions for specification ofsystem parameters. A panel discussion will followeach session. Panelists will be asked to focus onquestions that arise in their session and explore futuredirections for resolving them.For complete program, proceedings and registration infor-mation, write to:

=______ __- SPI E-_____=-____ P. 0. Box 1146

338 Tejon Placebr.u * r~dI.g ealth Palos Verdes Estates, California 90274

Phone: (213) 378-1216


acuity, and color normalcy. It was suggested that mock-up signsbe tested before extensive installations are made, lest they proveineffective.

Two papers followed that were concerned with the appearanceof signals in day and night situations. The first of these, by S.Kawai (Psychology Department, Chukyo University, Japan), re-ported studies made on the nonadditivity of lights in fairly closeproximity when seen at appreciable distances. Conditions forcomplete and incomplete additivity were described. The second,by H. Hofmann (Technical University of Darmstadt, West Ger-many), described color recognition of light signals under variousobservation conditions: adapting luminance, angular size of sig-nal, exposure time, and hue. The conclusion was reached that allthese conditions affect the certainty and reliability of the color rec-ognition.

Following these two papers on the appearance of signals weretwo papers on emergency of immediate reaction signals. The first,by C. J. Glass (Marine Safety Technology Division, U. S. CoastGuard), described the magnitude of the need for night and dayalerting and locating signals to recreational boaters in distress. Awide variety of visual signals are provided to alert the Coast Guardand to aid in locating distressed personnel and vessels. The sec-ond paper, by R. Hennessy (Human Factors Research, Inc.), dealtwith the design and use of tricolor glide-slope indicators in heli-copter approach to and landing on ships at sea. Improper designof the indicators causes faulty information about the location ofthe ship and results in delayed or missed landings. Proper opticaldesign and color arrangement, such as described by Hennessy, pro-vides an effective signal to the pilot of the helicopter.

E. J. Rinalducci (Psychology Department, University of Vir-ginia) discussed transient adaptation effects as causes of night visi-bility losses. Sudden increases or decreases in prevailing illumina-tion tend to decrease the observer's ability to recognize signals.The studies described attempted to find acceptable tolerance lev-els of increase or decrease of illumination.

The remaining three papers were concerned with the measure-ment of surface colors for signaling use. The first, by F. W. Bill-meyer (Chemistry Department, Rensselaer Polytechnic Institute),confined itself to the measurement of surface colors other than re-troreflective or fluorescent. The point was made that spectropho-tometers with geometries of diffuse illumination and normal view-ing (D/0) or its inverse equivalent (0/D), permitted under CIE rec-ommendation since 1967, may give results that are equally as goodas or better than can be obtained with geometries of 45° illumina-tion and normal viewing (45/0), or its inverse equivalent (0/45).

Meeting Reports continued from page 2186

Further introduction of the subject matter was focused in thenext two presentations. C. W. Jerome (Sylvania Lighting Center)described the purposes, activities, and organization of the Interna-tional Commission on Illumination. Next C. A. Douglas describedthe scope of the CIE Committee on Fundamentals of Visual Sig-naling. With these fine addresses the audience of over 75 personswas prepared for the technical program that was to follow.

The technical papers began with two comprehensive and inter-esting papers that treated visual signaling at great distances underfavorable as well as adverse conditions, as an aid to navigation incoastal waters. The first, by P. Blaise (French Lighthouse Ser-vice, Issy-les-Moulineaux), was concerned with long range visibili-ty of daytime signals. The second paper, by L. G. Reynolds(Trinity House Lighthouse Service, England), dealt with longrange nighttime visibility of fixed, flashing, and rotating light sig-nals. In the first paper the solution to making a mark visibleunder a variety of background and daylighting conditions was itsspherical dome shape and fluorescent red coating in several config-urations. The difficulty of the problem and the satisfactory na-ture of the solution was demonstrated by a large number of effec-tive color slides. In the second paper approximate methods ofcomputing effective intensity of flashing and rotating beaconswere used to evaluate their effectiveness and to predict luminousintensities required in favorable and adverse weather conditions.It was shown that the probability of seeing a light at its normalrange is about 45% on Britain's west coast, but only 21% on theeast coast.

It was this reporter's opinion that the treatment of effective in-tensity of flashing lights in the paper by L. G. Reynolds was intro-ductory to the third paper, by G. L. Howett (Sensory Environ-ment Section, National Bureau of Standards). This paper de-scribed how the procedure for computing the effective intensity offlashing lights, developed in 1957 by C. A. Douglas, was pro-grammed for automatic computer operation. It is remarkable howfew iterations of the underlying integrative process are required toreach a converging evaluation of the effective intensity of flashingor rotating light signals.

The next two papers were concerned with visibility and legibil-ity of signs. Each paper was presented by a member of the Psy-chology Department of Michigan State University, T. M. Allenand T. W. Forbes, who have been involved for many years withstudying sign legibility parameters. These parameters include:luminance and color contrast, illumination in night and day situa-tions, layout, letter aspects and stroke widths, observers' visual

I. Wu

L.G. Reynolds J. D. Moreland J.W. Moreau C. A. Douglas C.wW. Jerome

International and U.S. national members of the CIE Committee on Visual Signaling photographed during the Symposium. Photo U. S.Coast Guard.


F. W. Billmeyer C. F. Lyon 1. Nimeroff W. W. White T. H. Projector R. E. Conner

w.i M A 1Mrt4nen l- Terstiee AF. Stvne R Blaise W.C. Fisher_. .... . .. ----. , ... --- l-

- 477h AM r M �

This paper served as an excellent introduction to the presenta-tion by I. Nimeroff (Illuminating Engineering Group, NationalBureau of Standards) on the colorimetry of retroreflective materi-als. With materials that have strong geometric characteristics,color measurements should be made under conditions that simu-late actual use conditions. In daytime these are D/0, while atnight the materials for highway signs are illuminated unidirection-ally at entrance angles that range from near normal to 45° andviewed unidirectionally at angles that are small angular departuresfrom the incidence line.

The final paper, not announced prior to the meeting, by H. Ter-stiege [Photometry and Colorimetry Section, Federal Institute forMaterial Testing (BAM), Berlin], described color measurements ofnormal and printed retroreflective sheeting materials. Althoughseveral sources, D65, D75, and A were used with a variety ofgeometries, the author indicated that the geometry he preferredfor color measurement of retroreflective materials was 45/0 forboth daytime and nighttime color.

It was the intention of the organizers of this Symposium to pro-vide adequate time for discussion by those in attendance. For thisreason only a limited number of papers were invited for presenta-tion. All the authors formed their papers in the same general for-mat: first a review of their special segment of the field of visualsignaling, followed by a discussion of their current work. The in-troductory reviews in each presentation served as refreshers forthe old hands and as tutorials for the novices in visual signaling.Descriptions of the current work served to bring everyone in atten-dance abreast of the direction in which the broad field of visualsignaling is moving.

In summary, this reporter was impressed with the fact that eventhough visual signaling has been in use for several centuries, thereis still much that needs to be done. This is particularly true of theuse of new measuring devices in the evaluation of new materialsemployed in new and more complex situations than in earlieryears.

Of Optics continued from page A15

tration of normal and excited atoms in plasmas. Its use has beenreported in numerous papers by Soviet workers in spectroscopyand optics.

During World War I, Rozhdestvenskii took an active part in ex-pediting the production of optical glass, which was needed for do-mestic production of field binoculars, rangefinders, and other opti-cal instruments of a military nature. But Rozhdestvenskii's careerattained a special luster after the October Revolution: he wasamong those progressive scientists who strove to place science atthe service of the people. During the first year of Soviet power,Rozhdestvenskii proposed to the Commissariat of Education thatan institute of optics be created. He later wrote, "We were all in-spired by the same general idea-the creation of the Optics Insti-tute as a new type of institution in which scientific and technicalproblems would be inseparably linked together." The early daysof the Optics Institute were marked by a close relationship withthe Academy of Sciences: working at the Institute were Academi-cians I. V. Grebenshchikov, A. A. Lebedev, V. P. Linnik, A. N.Terenin, Corresponding Members A. I. Tudorovskii, T. P. Kravets,and a number of others.

Rozhdestvenskii was convinced of the need for a close relation-ship between theory and practice; he spent much time and efforton the organization and development of the Soviet optical indus-try. He himself worked on theoretical problems-spectral and

atomic structure theories-and in the field of applied optics, whichhe enriched by his studies of microscope imaging. He was one ofthe first to introduce the idea of partially coherent light.

Rozhdestvenskii was a founder of the outstanding Soviet schoolof optics. His students and followers work to this day in institutesof the Academy, at Leningrad University, and in many other insti-tutions. Among his students are the outstanding scientists, Aca-demician A. N. Terenin and Corresponding Member E. F. Gross.The author of this essay also belongs to that group.

A. N. Terenin began his scientific work in the 1920's by studyingthe optical excitation of atoms. The results he obtained are wide-ly known both in the Soviet Union and abroad. His subsequentstudies included optical excitation of molecules; he made manynew discoveries in the field of photochemistry. He developed anoriginal method for finding the dissociation heat of diatomic mole-cules based on the measurement of the frequency of exciting lightwhich causes the line of one of the atoms composing the moleculefirst to appear in the fluorescence spectrum. Terenin also ana-lyzed, using spectroscopic methods, the elementary photochemicalprocesses in triatomic and tetratomic haloid compounds. A greatnumber of his investigations involved the spectroscopy of adsorbedmolecules. Terenin gave much attention to molecular lumines-cence phenomena, and he identified the metastable state of mole-cules as the triplet state, thereby bringing clarity to the interpreta-tion of the mechanism of longterm luminescence. An extensive se-ries of papers on the luminescence of phosphor crystals was begunon his initiative.

The papers of Corresponding Member T. P. Kravtsev on photo-chemical processes in silver haloid compounds and on the natureof the latent photographic image belong to the field of molecularspectroscopy. The work of E. F. Gross on scattering and absorp-tion of light showed great originality. Since they are associatedwith the approach developed by L. I. Mandelshtam, they will bediscussed later.

Optical research was an important part of the varied activity ofAcademician L. I. Mandelshtam. In 1922, he developed, simulta-neously with and completely independently of the French physi-cist Brillouin, the theory of light scattering by thermal waves incrystals. Scattering of this type is accompanied by a change inwavelength. It provides a new method for studying thermal vibra-tions in solids. However, the predicted change in wavelength is sosmall that detection of it experimentally encounters serious dif-ficulties. But through their experiments on quartz crystals L. I.Mandelshtam and G. S. Landsberg discovered a new and previous-ly unknown type of scattering associated with an appreciablygreater change in wavelength. Simultaneously, the Indian physi-cist, C. V. Raman, detected scattering of this type in fluids. Sub-sequently, this new type of scattering was known in the world liter-ature as Raman scattering, although it undoubtedly should be as-sociated also with the names of the Soviet physicists Mandelshtamand Landsberg. In Soviet literature it is known as combinationscattering. [It should not be forgotten, in this context, that little,if any, information was getting out of Russia in the early twen-ties. MIEd. I

Raman scattering is one of the most important events in opticsin the first half of this century. Producing an enormous body ofliterature in all countries where optical methods are used to studysolids and fluids, molecular structure, and the nature of chemicalprocesses, Raman scattering is essential for studying the structureof organic molecules and crystals. At the present time, when la-sers permit us to study nonlinear optical phenomena, stimulatedRaman scattering of light is of special interest.

E. F. Gross was the first to detect the scattering of light by ther-mal waves in solids predicted by Mandelshtam. The experimentaldata completely agreed with the theory. Then, Gross discoveredanother new effect: he found that in light scattering by fluids theRayleigh line is broadened and accompanied on both sides by a

background called wings. It was shown that study of the wings


makes it possible to explain many features of the structure offluids and amorphous bodies. Later Gross, while working on the

absorption spectra of crystals, discovered the hydrogenlike spec-trum of excitons-quasi-particles formed in the crystal latticewhich had been predicted theoretically by Ya. I. Frenkel. The dis-covery of excitons opened the way to a large amount of experimen-tal and theoretical research in the Soviet Union and abroad.

The work of Academician S. I. Vavilov covered an enormous

range of phenomena. He was most interested in problems relatingto the properties of light, both in classical and quantum theory.He showed that interference is dependent on the type of emitter-dipole, quadrupole, etc. Polarization of light in photolumines-cence is also dependent on the nature of the elementary emitters.On the basis of these conclusions, Corresponding Member P. P.Feofilov demonstrated that fluorescence of dyes in solutions, and

also of uranium glass, is due to dipole radiation, and he discoveredlines corresponding to both electric and magnetic dipoles in the lu-minescence spectra of uranium in crystals.

Another unique phenomenon discovered in Vavilov's laboratoryis the luminescence of an electron moving faster than the speed oflight in a medium. This phenomenon was detected by P. A. Cer-

enkov and is now known as the Cerenkov-Vavilov phenomenon.Its existence follows from classical wave considerations, but a com-plete theory for it was obtained only after it had been observed ex-

perimentally by I. E. Tamm and I. M. Frank. The Cerenkov-Va-vilov phenomenon is important in nuclear physics as a method fordetermining the velocity of fast nuclear particles. It also has accu-mulated a large body of literature. In 1958, Cerenkov, Frank, andTamm were awarded the Nobel Prize for their discovery. Theywere all subsequently made members of the Academy of Sciences.

An interesting group of papers by Vavilov involves a study of theeffect of extremely weak light fluxes on the human eye. It wasfound that the eye adapts so well that a flux of a few ten of pho-tons per second through the pupil initiates vision: fluctuationphenomena also occur. New information about the eye was alsoobtained. It seems that the retina of the human eye is sensitive toultraviolet radiation, but under normal conditions this is not aproblem because of the strong absorption of ultraviolet rays by thelens of the eye.

However, Vavilov's fundamental interest in optics was the studyof luminescence. He discovered a number of general laws deter-mining the basic properties of the luminescence of dye solutions.

Vavilov, as Rozhdestvenskii, had the honor of creating a largeschool of Soviet specialists in optics. For a long time the director

of the Physics Institute of the Academy of Sciences of theU.S.S.R., he saw to it that optical and spectroscopic subjects had aplace in the scientific work plan at this Institute.

Workers in the Academy were always interested in combiningscientific work with practical tasks, but this tendency becameespecially strong in the post-revolutionary period. An optical in-dustry, absent in Czarist Russia, was successfully developed. In acomparatively short time it was able to produce optical glass, cam-eras, microscopes, and measuring and optical instrumentation. Inaddition to Rozhdestvenskii's efforts, other members of the Acade-my helped develop applied optics. Important services in the de-velopment of the technology of founding and finishing optical glasswere rendered by Academician I. V. Grebenshchikov. Corre-sponding Member A. I. Tudorovskii designed optical systems andtrained the first cadres of optical designers. Academicians A. A.Lebedev and V. P. Linnik worked on new types of interferometersand a number of other original optical instruments and methodsfor optical measurements. Academician I. V. Obreimov appliedFresnel diffraction to the precise measurement of the refractive in-dices of glasses. Vavilov's work on the luminescence of phosphorcrystals played an important role in the development of lumines-cent light sources and luminescing screens used in various instru-ments.

The growth of spectral analysis had great.economic significance.

The fast growing metallurgical and other industries required pre-cise, simple, and fast analytical methods. This need was met bythe work on spectral analysis performed by a large group at theAcademy's Physics Institute under the direction of AcademicianG. S. Landsberg. New devices-steelscopes and steelometers-were evolved, which permitted spectral methods of grading steelsand nonferrous metal alloys to be introduced rapidly into the in-dustry. Later, these simple methods were replaced by quantita-tive spectral analysis, and automated spectral-analytical devices-quantometers-were produced. At the same time, attention wasgiven to molecular spectral analysis, which is widely used in thechemical industry. In Leningrad, Corresponding Member S. E.Frish and his co-workers developed methods of quantitative spec-tral analysis of gases for industrial use.

In 1936, the Commission on Spectroscopy was established in theAcademy by G. S. Landsberg. At first, the Commission concen-trated on developing methods of spectral analysis and having themput into practice, but soon it outgrew these limits and engaged inwide-range planning for all branches of spectroscopy. At the pres-ent time, the Academy has a Joint Council on the Combined Prob-lems of Optics. It consists of three scientific committees consid-ering the problems of Atomic and Molecular Spectroscopy, Lumi-nescence and its Industrial Applications, and Coherent and Non-linear Optics.

In the last decade or two, there have been important discoveriesin international science which have opened up new directions foroptical research and new areas for optical applications. Academyscientists have made a large contribution to these discoveries.The discovery of lasers should be mentioned first. In 1954, twoworkers at the Physics Institute of the Academy of Sciences (sub-sequently Academy members), N. G. Basov and A. M. Prokhorov,proposed that stimulated transitions be used to generate micro-wave frequencies. An ammonia laser was then developed. Theirwork was awarded a Lenin Prize in 1959 and soon received world-wide recognition, as evidenced by their winning (with the Ameri-can physicist C. H. Townes) the Nobel Prize in 1964. A littlelater, N. G. Basov and V. M. Vul developed the semiconductorlaser.

Work on solid state lasers stimulated studies into the spectros-copy and luminescence of activated crystals, which were begun inthe Soviet Union by P. P. Feofilov in the 1950's. The results ofthis work were fundamental to the development of the first lasers,which operated in a four-level mode (fluorite with divalent samar-ium and trivalent uranium).

Another outstanding discovery was that of holography. At thebeginning of the 1960's, Yu. N. Denisyuk (who was elected a Corre-sponding Member of the Academy in 1970) developed and experi-mentally verified a method of wave photography of three-dimen-sional objects based on the recording of the amplitudes and phasesof the wavefront of scattered light. The first such photographs(holograms) were obtained before cw lasers were developed. Sub-sequently, the use of coherent light greatly expanded the possibili-ties of holography. Denisyuk recorded the 3-D wavefront on thickphotographic plates, which is the chief difference between his ap-proach and that of Gabor, who in his first experiments recordedonly wavefronts diffracted from plane objects. The work of Yu. N.Denisyuk, awarded a Lenin Prize in 1970, permits one to recon-struct the size and color of objects.

Another field for the application of optical and spectral methodsis space research. Satellites and rockets have made it possible tostudy the spectrum of the sun and other astronomical objects inthe ultraviolet and soft x-ray regions. Spectroscopic study of thesolar corona was begun, requiring both theoretical calculations andspecial measurements under terrestrial conditions. One of theproblems is the study of the spectra of multiply ionized atoms.Work in this field, and investigations into laser photochemistryand molecular spectroscopy, is going on in a new institute of the


Academy, the Institute of Spectroscopy, under the direction of S.L. Mandelshtam.

A broad range of nonlinear optics problems are being studied by

Corresponding Member R. M. Khokhlov and his group at MoscowUniversity.

The U.S.S.R. Academy of Sciences is presently engaged in wide-

ly ranging research in optics and in spectroscopy. In the new in-

stitutes of the Siberian Branch of the Academy, spectroscopic top-ics occupy an ever-growing area. The Institute of Atmospheric

Optics in Tomsk operates successfully under the direction of Cor-responding Member V. E. Zuev. The relationship between the in-

stitutes of the Academy and those of other departments and uni-versities is becoming closer, although there is much to do in thisregard. The academies of the various republics are associated

with the U.S.S.R. Academy through the Council on Coordinationand the committees on scientific problems; they also pay a gooddeal of attention to optical research. In the Byelorussian Acade-my of Sciences, research is carried out on lasers, especially dye la-

sers. In the Ukraine, molecular spectroscopy receives much atten-

tion, especially low-temperature absorption and luminescencespectra of organic crystals and exciton absorption. In the PhysicsInstitute of the Estonian Academy of Sciences, the spectroscopy of

crystals has an important place. In the Latvian and LithuanianAcademies of Sciences, collision theory and the calculation of

atomic energy states are investigated. The Kazakh Academy hashad success in using spectral-analytic methods for geological re-

search. The Uzbek Academy is concerned with problems of mo-lecular spectroscopy. Laser research is an important part of the

work of the Armenian Academy. This list-far from complete-illustrates the vast extent of the research.

Optics is making an ever increasing contribution to allied sci-

ences and technologies. Laser sources of light make it possible toinvestigate problems of coherent and nonlinear optics, to use lightchannels to transmit information over large distances, includingthose of outer space, and to increase the accuracy of measurementsby several orders of magnitude. Holographic methods, which pro-

vide new ways of recording and processing information, are des-

tined to play a large role in computer technology and cybernetics.Renowned in the past for its work in optics, the U.S.S.R. Acade-

my of Sciences will undoubtedly in the future play a leading role in

the development of optical and spectroscopic research in all itsphases.

Meetings Calender continued from page A22

15-19 15th Nat. Assembly of Soc. for Appl. Spectrosc., Phila-delphia Jeanette Grasselli. Standard Oil Co. (Ohio)4440 Warrensville Ctr. Rd., Cleveland, Ohio 44128

23-28 SMPTE, 119th Tech. Conf. and Equipment Exhibit,Chicago D. Courtney, 9 E. 41st St., New York, N. Y.10017

June21-24 AAS 148th Mtg., Haverford College L. W. Frederick,

c/o Leander McCormick Obs., Box 3818, Univ. Sta-tion, Charlottesville, Va. 22903

August

9 10th Australian Spectrosc. Conf., University of WesternAustralia, Nedlands, W.A. A. Walsh, CSIRO Div.of Chemical Physics, P.O. Box 160, Clayton, Victoria3168, Australia

September .26-Oct. 1 SMPTE, 120th Tech. Conf. and Equipment Exhibit,

New York D. Courtney, 9 E. 41st St., New York,N.Y. 10017

November15-19 Fed. of Analytical Chemistry and Spectroscopy Soc.,

Philadelphia Jeanette Grasselli, Standard Oil Co(Ohio), 4440 Warrensville Ctr. Rd., Cleveland, Ohio44128

December? AAS 149th Mtg., Univ. Hawaii L. W. Frederick, Box

3818, Univ. Sta., Charlottesville, Va. 22903

1977April

? AAS 150th Mtg.,'Atlanta L. W. Frederick, Box 3818,Univ. Sta., Charlottesville, Va. 22903

May1-6 SMPTE, 121st Tech. Conf. and Equipment Exhibit,

Los Angeles D. Courtney, 9 E. 41st St., New York,N.Y. 10017


Papers to appearin subsequent issues

Correspondence to these authors will be forwarded Ifaddressed individually in care of the Managing Editor

Infrared Radiometer for the Pioneer 10 and 11 Missions to Jupiter-Ben-der, Callaway, Chase, Moore, and Ruiz

Stimulated Emission from Nuclei-Byrne, Peters, and AllenMinimization of the Prime Power Consumption of a Coupling-Modulated

Gas Laser Transmitter-DegnanAnalytical Description of a Fabry-Perot Spectrometer. 3: Off-Axis Behav-

ior and Interference Filters-HernandezThe Star Coupler: a Unique Interconnection Component for Multimode

Optical Waveguide Communications Systems-Hudson and ThielUnit Color-Difference Figures Derived from the Proposed CIE 1976 L*a*b*

Space-Rich and BillmeyerStability of Optical Resonators with an Active Medium-Ganiel and Silber-

bergHigh Temperature Absorption in CO2 at 10.6 Am-Strilchuk and Offenber-

gerRemoval of Pedestals and Directional Ambiguity of Optical Anemometer

Signals-Durst and ZareSpherically Corrected Reflecting Objective for Unit Magnification-Miel-

enzSize-Refractive Index Distribution of Clear Coastal Water Particulates from

Light Scattering-Brown and GordonTransverse-Flow Quasi-cw HF Chemical Lasers: Design and Preliminary

Performance-Gagng, Mah, and ConturieSpeckle-Shearing Interferometric Technique: a Full-Field Strain Gauge-

Hung, Rowlands, and DanielTheoretical Comparison of Singly Multiplexed Hadamard Transform Spec-

trometers and Scanning Spectrometers-Larson, Crosmun, and TalmiLaser Isotope Separation Using Two-Photon Selective Excitation; Its Quan-

tum Efficiency and Separation Factor-LiuSingle-Crystal Electrooptic Thin-Film Waveguide Modulators for Infrared

Laser Systems-LotspeichPhase Difference and Angle-of-Arrival Fluctuations in Tracking a Moving

Point Source-Lutomirski and BuserAirborne Laser Doppler Velocimeter-Munoz, Mocker, and KoehlerCO2 Laser Absorbtion Coefficients for Determining Ambient Levels of 03,

NH3, and C2 H4 -Patty, Russwurm, McClenny, and MorganOptical Quality of Pulsed Electron-Beam Sustained Lasers-Pugh, Wal-

lace, Jacob, Northam, and DaughertyNormal-Mode Approach to Wave Propagation in the Turbulent Atmo-

sphere-ShapiroAtmospheric Gas Absorption at DF Laser Wavelengths-Spencer, Denault,

and TakimotoHigh Resolution Luminescence Spectrometer. 2: Data Treatment and

Corrected Spectra-Vo Dinh Tuan and WildSpectral Remote Sensing of Temperature Distribution in Semitransparent

Solids Heated by an External Radiation Source-Viskanta, Hommert,and Groninger

Small Dye Laser in a Semiunstable Resonator Pumped by an Argon-JetGuided Spark-Weysenfeld

Physical Model for Predicting Grinding Rates-Wiese and WagnerThreshold Detection in an On-Off Binary Communications Channel with

Atmospheric Scintillation-Webb and MarinoTwo Asymmetric Hadamard Transform Spectrometers-Harwit, Phillips,

King, and BriottaGround Illumination from a Turbid Cloudless Sky-NagelInfluence of Longitudinal Vibrations on the Diffraction Images of Bright In-

coherent Disks-Singh, Rattan, and MaggoCharacteristic Fringe Function for Time-Average Holography of Periodic

Nonsinusoidal Vibrations-Gupta and SinghMoire Topography-ChiangVersatile Nebular Insect-Eye Fabry-Perot Spectograph-MeaburnHolographic Ruby Laser with Long Coherence and Precise Timing-Young

and HicksTwo-Film Reflection Polarizers: Theory and Application-Ruiz-Urbieta,

Sparrow, and ParikhNarrowband Ultraviolet Vapor Filter-Senitzky

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Lineshape Measurement for Coupling to Waveguide Modes in the Prism-Film Coupler-Galantowitz

Mode Calculations in Unstable Resonators with Flowing Saturable Gain. 1:Hermite-Gaussian Expansion-Siegman and Sziklas

Double-Beam Two-Channel Wavelength-Modulated Reflectometer-Kar-dux and Krusemeyer

Space Reflectors for Radar and Astronomy-YaterNoise and Other Artifacts in OTF Derived from Image Scanning-DuttonLoss Measurements in Optical Fibers. 1: Sensitivity Limit of Bolometric

Techniques-CohenSubmillimeter-Wave Atmospheric and Astrophysical Spectroscopy-Beck-

man and HarriesVertical Distribution of NO, NO2 and HNO3 as Derived from Stratospheric

Absorption Infrared Spectra-Fontanella, Girard, Gramont, andLouisnard

Prediction of Nighttime Driving Visibility from Laboratory Data-Duni-* pace, Strong, and Huizinga

Spherical Abberation Measurement with a Shearing Interferometer UsingFourier Imaging and Moire Method-Yokozeki and Ohnishi

Kinetic Model and Computer Simulation of Continuous Wave DF-CO2Chemical Transfer Lasers-Baumann, Blauer, Zelazny, and Solomon

Computation of RMS Spot Radii by Ray Tracing-ForemanDrift in Interference Filters. 2: Radiation Effects-TitleMultiplexed Dispersive Spectrometers Using Reduced Background Infrared

Detectors-Wyatt and EsplinDigital Wavefront Measuring Interferometer for Testing Optical Surfaces

and Lenses-Bruning, Herriott, Gallagher, Rosenfeld, White, andBrangaccio

Laser Resonators with Polarizing Elements-Eigenstates and Eigenvaluesof Polarization-Junghans, Keller, and Weber

Wind and Refractive-Turbulence Sensing Using Crossed Laser Beams-Wang, Clifford, and Ochs

Correction of Parabolic Errors in Fabry-Perot Interferometers-Nettlefieldand Ramsay

Parasitic Suppression in Large Aperature Nd:Glass Disk Laser Amplifiers-Glaze, Guch, and Trenholme

Optical-Waveguide Band-Rejection Filters: Design-Matsuhara and HillThree-Dimensional Unstable Resonator Calculations with Laser Medium-

RenschImproved Thermoplastic-Photoconductor Devices for Holographic Record-

ing-Colburn and TompkinsOptimal Filter Design for Annular Imaging-Fedotowsky and LehovecLidar Measurement of Temperature: a New Approach-MasonSpectral Analysis and Cross-Correlation Techniques for Photon Counting

Measurements on Fluid Flows-Durrani and GreatedResponse Calculations for Light-Scattering Aerosol Particle Counters-

Cooke and KerkerConstruction of Photolithographic Phase Gratings Using the Fourier Image

Effect-Kodate, Takenaka, Kamiya, and YanaiEnvelope Interferometry for Large-Scale Processing-MacovskiDrift in Interference Filters. Part 1.-Title, Pope, and AndelinPerformance Characteristics of Single Point Diamond Machined Metal Mir-

rors for Infrared Laser Applications-Saito and SimmonsEvaluation of r,, for Propagation Down Through the Atmosphere-Fried

and MeversFar Field Diffraction Patterns of Circular Gratings-Fedotowsky and Leho-

vecOptimum Adaptive Imaging Through Atmospheric Turbulence-ShapiroOutput Properties of Short-Pulse Gain-Switched Lasers-CaspersonLaser Doppler Velocimeter as an Optoelectronic Data Processing System-

Dubnitshev, Koronkevich, Sobolev, Stolpoyski, Vasilenko, and UtkinWavelength Standards for Use with a BRV Source-NewsomMultiple Docking Adapter Window for the S-190 Experiment-Gimlett

and GarbaccioLoss Measurements in Optical Fibers. 2: Bolometric Measuring Instru-

mentation-Cohen, West, Lazay, and SimpsonThe Abbe or the Duffieux-PappuUnit for Wavenumber-ChamberlainNomograph for the Calculation of the Index of Refraction of a Prism-

ZankerGaAs Laser Diode Pumped Nd:YAG Laser-Conant and RenoSea Echo Measurements Made with 1.06-,um Laser Radiation-Stamm and

HarrisQuadruple-Exposure Technique in Stroboscopic Holographic Interferome-

try-Chopra and Bhatnagar

A28 APPLIED OPTICS / Vol. 13, No. 10 / October 1974

Real Time Display of Velocity Distribution on a Surface by Using Ultrason-ic Laser Light Frequency Shifter and TV System-Sato, Nakatani,and Ueda

Convergence of a Spectrum Shaping Algorithm-Liu and GallagherModified Ray Tracing in a Dielectric Rod-PaskInformation Content in Remote Sensing: Comments-Wang and GoulardOptical Testing: a Bibliography of Various Methods-Malacara, Cornejo,

and MurtyLight Scattering by a Spheriodal Particle-Asano and YamamotoEstimating the Refractive Error in Optical Measurements of Transport

Phenomena-Anderson, Stevenson, and ViskantaHigh-Precision Scanning Ellipsometer-Aspnes and StudnaDetection Probabilities for Fluctuating Infrared Targets-Clow, Hansen,

and McNoltyRefractive Index of Nd:CaF2 and Some Nd Doped Glasses as a Function of

Wavelength, % Neodymium, and Temperature-Gunter and ClossDispersion-Optimized Optical Single-Mode Glass Fiber Waveguides-Jiir-

gensenMeasurement of Strain Distribution in Plane Metal Plate by Optical Spatial

Filtering-Nagae, Iwata, and NagataDer Einfluss der Szintillation auf den K-Faktor der Sonnenfleckenrelativ-

zahl-Paperlein and PachaliAnalysis of Optically Pumped CO2 Laser-Pirkle and SigillitoWoven Fiber Optics-Schmidt, Courtney-Pratt, and RossMeasurement of the Velocity of Blood Flow (in vivo) Using a Fiber Optic

Catheter and Optical Mixing Spectroscopy-Tanaka and BenedekRelative Effects of Temperature Changes and Emissivity Changes on Dif-

ferences in Radiance-WolfeDynamics of Human Teeth in Function by Means of Double Pulsed Holog-

raphy; an Experimental Investigation-Wedendal and BjelkhagenIrradiance Distribution, Resolution, and Size Estimates in Diffraction Lim-

ited Imagery of Extended Circular Targets-Yu, Otterman, and Rav-noy

MTF of Proximity-Focused Image Tube in Polychromatic Light-Nijhaw-an, Datta, and Sharma

Gamma Ray Imaging with Stochastic Aperatures-May, Akcasu, and KnollTechnique for Instantaneous Recording of Intensity Distributions of Visible

and Near Infrared Laser Beams-LuckElectrooptical Focus and Alignment-KaestnerFar Infrared Transmission and Reflection of Irtran 1 Through Irtran 6 at

Low Temperatures- Wijnbergen and KellyColor Presentation of Plasma Flows and Fast Particles in a Hypervelocity

Accelerator-Igenbergs, Court-Palais, Fisher, and StehleRemote Atmospheric Sensing with an Airborne Laser Absorption Spectrom-

eter-Menzies and ChahineHolographically Generated Lens-Richter and CarlsonRefractive Index and Diameter Determinations of Step Index Optical Fibers

and Preforms-Presby and MarcuseAdjustable Aperture Stop to Control the Divergence and Orientation of the

Beam Emerging from a Vacuum Ultraviolet Monochromator-Hunterand Chaimson

Modes of a Diffraction Grating Optical Resonator-Hardy and TrevesSky Brightness and Polarization During the 1973 African Eclipse-ShawEvaluation of Large Aberrations Using a Lateral-Shear Interferometer Hav-

ing Variable Shear-Rimmer and WyantScanning Kirkpatrick-Baez X-Ray Telescope to Maximize Effective Area

and Eliminate Spurious Images; Design-KastRemoval of Instrument Signature from Mariner 9 Television Images of

Mars-Green, Jepsen, Krezner, Ruiz, Schwartz, SiedmanPrecision Beam Splitters for CO2 Lasers-FranzenSelf-Guiding Flashlamp-Pumped Dye Lasers-Burlamacchi, Pratesi, and

RonchiThree-Frequency Nonlinear Heterodyne Detection. 1: cw Radar and Ana-

log Communications-Teich and YenAberrations of Ellipsoidal Reflectors for Unit Magnification-MielenzThree-Frequency Nonlinear Heterodyne Detection. 2: Digital Communi-

cations and Pulsed Radar-Teich and YenEffect of Collision Narrowing on Atmospheric Transmittance-ArmstrongAlignment Technique for Unstable Resonators-Hanlon and AikenSubmillisecond Development of Thermoplastic Recordings-Maloney and

GravelEffect of Temperature Gradients on the Wave Abberation in Athermal Op-

tical Glasses-Reitmayer and SchroederRemoval of Seeing and Instrumental Blur Effects from Astronomical Scan-

ner Observations-Clements and Herman

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Characteristics of Deterministic Phase Codes for Holography-Sato andShimizu

Improvement of Birefringent Filters. 2: Achromatic Waveplates-TitleOptical Constants of Sulphuric Acid: Application to the Clouds of Venus-

Palmer and WilliamsExcitation of the Fundamental and Low-Order Modes of Optical-Fiber

Waveguides with Gaussian Beams. 2: Offset Beams-Imai and HaraFlashlight-Size External Cavity Semiconductor Laser with Narrow-Line-

width Tunable Output-Heckscher and RossiExtension of 3p 3s Ion Lasers into the Vacuum Ultraviolet Region-

EltonOn the Design of Simple Rotating Stigmatic Concave Grating Monochroma-

tors-PoueyAdvances in Bleaching Methods for Photographically Recorded Holograms-

GraubeMultistep Handle Test-Noble, Malacara, and CornejoMass Absorption Indices of Various Types of Natural Aerosol Particles in

the Infrared-FischerLight Modulation with Multilayer Thin Films-ItoMulticolor Imagery from Holograms by Spatial Filtering-IhLight Intensity of the Fundamental Mode TEMOO of a He-Ne Gas Laser

Without Brewster Windows: Achievement of a Polarized RectilinearLaser Beam of Stable Intensity-Mas, Blancher, and Roig

Intensity Fluctuations of Optical Radiation in Scattering Media-Borovoy,Kabanov, and Saveliev

Transient Thermal Blooming of Long Laser Pulses-Buser and RohdeInfrared Interferometer with a Scanned Aperture-EdwinDiffraction Losses Associated with Tungsten Lamps in Absolute Radiome-

try-BoivinLow-Loss FEP-Clad Silica Fibers-Kaiser, Hart, and BlylerSpectral Line Selection of Carbon Monoxide Lasers-RiceComments on: Signal Processing for a Signal with Poisson Noise-ShapiroDetermination of Transmittance Ratio of a Compensator-KothiyalFourier Transform Lens: a Misnomer-PappuMode Selective Filtering by a Coupling Mechanism between Glass Fiber

and Thin-Film Slab Waveguide-Goben, Begley, and DavarpanahChirped Fourier Spectroscopy. 1: Dynamic Range Improvement and

Phase Correction-SheahenAnalysis of a Computer-Generated Binary-Phase Hologram-Ransom and

HentonReal-Time Holographic Motion Pictures Capable of Recording Front Sur-

face Detail from a Random Velocity Vector: Comments-AbramsonEstimation of the Depth of Sunlight Penetration in the Sea for Remote

Sensing-Gordon and McCluneyComputed Relationships between the Inherent and Apparent Optical Prop-

erties of a Flat Homogeneous Ocean-Gordon, Brown, and JacobsCoherent Detection Signal-to-Noise-FinkSpeckle Noise Reduction by Random Phase Shifters-Matsumura10.6-pm Absorption Dependance on Roughness of UHV Coated Sup-

ersmooth Mirrors-Saito, Kurdock, Austin, and SoileauCorrection for Errors in Optical Pulsed Range Measurements-MiyakeOptical Interpolation with Application to Array Processing-Felstead and

Tenne-SensRotational Raman Interferometric Technique to Measure Gas Tempera-

tures-ArmstrongMultiple Scattering Measurements as a Function of Wavelength by Use of a

Dye Laser-CohenHolographic Doppler Imaging of Rotating Objects-Aleksoff and Christen-

senHolographic Recording by Dye-Sensitized Photopolymerization of Acrylam-

ide-Sugawara, Murase, and KitayamaVisibility of Distant Mountains as a Measure of Background Aerosol Pollu-

tion-Porch, Ensor, and CharlsonNonlinear Longitudinal KTN Modulator-FoxFocusing Effects in Interferometric Analysis of Graded-Index Optical Fi-

bers-Stone and BurrusEffects of Periodic Nonsinusoidal Vibrations in Matched Filtering for De-

tection of Signals Buried in Noise of Uniform Spectral Density-Singhand Gupta

Mach-Zehnder Interferometer Data Reduction Method for Refractively In-homogeneous Test Objects-Hunter and Schreiber

Propagation Charactoriatica of Partially Motal Clad Optical Guido; MetalClad Optical Strip Line-Yamamoto, Kamiya, and Yanai

Johnson Noise Limited Operation of Photovoltaic InSb Detectors-Hall,Aikens, Joyce, and McCurnin

A30 APPLIED OPTICS / Vol. 13, No. 10 / October 1974

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absorber for solar power

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