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Kirchhoff-Institut
für Physik
Prof. Dr. Petrich Biophotonics I (WS 2017/18) 1
Biophotonics I W. Petrich
Slides of lecture #01 October 16th, 2017
http://www.kip.uni-heidelberg.de/biophotonik/teaching
Biophotonics I Imaging systems
Scattering of light
Biophotonics II Biospectroscopy
Lasers in medicine
Kirchhoff-Institut
für Physik
Prof. Dr. Petrich Biophotonics I (WS 2017/18) 2
Biophotonics I general remarks
BIOPHOTONICS I (WS 2017/18)
I. Imaging Systems human vision
microscopy
II. Light Scattering Mie scattering
light propagation in tissue
BIOPHOTONICS II (SS 2018)
III. Biospectroscopy
IV. Lasers in medicine
Literature:
• Bergmann-Schäfer, Optik (Walter de Gruyter)
• E. Hecht, Optik (Addison-Wesley)
• J. Bille, W. Schlegel, Medizinische Physik 3 (Springer)
• P.N. Prasad, Biophotonics (Wiley)
• T. Vo-Dinh, Biomedical Photonics Handbook (CRC
Press)
• V.V Tuchin, Handbook of Optical Biomedical Diagnostics
(SPIE Press)
• C.F. Bohren, D.R. Huffmann, Absorption and Scattering
of Light by Small Particles (Wiley VCH)
• L.V. Wang, H.-I. Wu, Biomedical Optics (Wiley)
• Lecture „Biophotonics I“ will be credited with 2 CP subject to successfully passing the exam
• The exam („Klausur“) will be a written examination on February 5th, 2018
• If you intend to obtain credit points, i.e. to participate in the exam, you will need to register (further
information will follow)
Kirchhoff-Institut
für Physik
Prof. Dr. Petrich Biophotonics I (WS 2017/18) 3
Biophotonics I I.1. human vision
Kirchhoff-Institut
für Physik
Prof. Dr. Petrich Biophotonics I (WS 2017/18) 4
Biophotonics I I.1. human vision
H. Helmholtz, Archiv für Ophthalmologie , March 1855, Volume 2, Issue 2, pp 1-74
Kirchhoff-Institut
für Physik
Prof. Dr. Petrich Biophotonics I (WS 2017/18) 5
Biophotonics I I.1 human vision
Kirchhoff-Institut
für Physik
Prof. Dr. Petrich Biophotonics I (WS 2017/18) 6
Biophotonics I REMINDER: what is a focal length? What is a diopter?
n2 n1
s0 s1
l1 l0 R
R
nn
s
n
s
n
slandsleifor
l
sn
l
sn
Rl
n
l
n
Rl
ns
l
nR
l
ns
l
n
Rl
nRs
l
nR
l
nRs
l
n
RsRl
nRsR
l
n
d
dL
principlesFermat
lnlnL
pathlengthoptical
RsRRsR
RsRRsRl
RsRRsRl
12
1
2
0
1
1100
1
12
0
01
1
2
0
1
1
21
1
2
0
10
0
1
2
1
21
1
22
0
10
0
1
!
1
1
20
0
1
1201
1
2
1
2
1
2
1
22
1
0
2
0
22
0
)1cos..(0
1
0
0sinsinsinsin
0sin)(22
sin)(22
:'
:
cos)(2)(
)180cos()(2)(
cos)(2)(
)(
)(
12
2110
12
1001
lengthfocalbackRnn
nsfsfor
lengthfocalfrontRnn
nsfsfor
R
nn
f
n
f
n
n
n
f
f
Rff
12
0
1
1
2
2
1
1
0
01
Note that 1.)
2.) D
refractive power („Brechkraft“)
unit: 1 Diopter = 1 D = 1/m
„paraxial approximation“:
Kirchhoff-Institut
für Physik
Prof. Dr. Petrich Biophotonics I (WS 2017/18) 7
Biophotonics I REMINDER: what is the power of a lens (“Brechkraft”)?
n1
s0 s2
R1
fRRn
ss
followsitnairin
dFdlensesthinfor
dFRR
nns
n
s
n
R
nn
s
n
s
nand
R
nn
s
n
s
n
surfacestwo
111)1(
11
:)00,1(
)0)(;0(
)(11
)(
21
2
20
1
21
12
2
1
0
1
2
21
2
1
1
2
1
12
1
2
0
1
D
„Gauß‘sche Linsenformel“
For two thin lenses (or two near-by surfaces) one can show that D = D1+ D2+ 2D1 D2d/n2
D1+ D2
n2 n1
R2
d
Kirchhoff-Institut
für Physik
Prof. Dr. Petrich Biophotonics I (WS 2017/18) 8
Biophotonics I I.1 human vision
Snellen chart
Landolt
rings
Picture taken from: wikipedia.org
Kirchhoff-Institut
für Physik
Prof. Dr. Petrich Biophotonics I (WS 2017/18) 9
Biophotonics I REMINDER: diffraction limit
d
b
A) diffraction from a thin single slit in the far field (1-D)
p
d
2
d2phase difference between first and last beam:
phase difference between 1st and pth beam:
2
2*
)(0)1(32)(0
2)(03
)(02
)(01
sin
sinsin
~lim~
2sin
2sin
~)1(
;;
b
b
bEEI
p
ep
bEeeeee
p
EE
eep
EEee
p
EEe
p
EE
ttottot
p
tkxipiiiitkxi
tot
itkxiitkxitkxi
B) diffraction from a circular aperture in the far field (2-D)
2
10
sin
)sin(2
ka
kaJII
J1: 0th order Bessel function
• Maximum of J1 at =0
• first minimum of J1 at sin()=1,22/D
Rayleigh‘s criterion for „resolution“: „Diffraction maximum from one
object coincides with diffraction minimum of second object“