Noisy Light SpectroscopyDarin J. Ulness

Department of ChemistryConcordia College, Moorhead, MN

Noisy Light Spectroscopy• What is noisy light?• History• Theory• Experiment• Applications and results• Context• The future of noisy light

spectroscopy

What is Noisy Light?•Broadband•Phase incoherent•Quasi continuous wave

Elet

ric F

ield

Stre

ngth

Time

Noi

sy L

ight

Spe

ctru

m

Frequency

Time resolution onthe order of the correlation time, tc

What is Noisy Light?Ultrashort pulse

Shor

t Pul

se S

pect

rum

Frequency

Time resolution onthe order of the pulse width

Coherent Phase locked

Time

•Broadband•Phase incoherent•Quasi continuous wave

What is Noisy Light?N

oisy

Lig

ht S

pect

rum

Frequency

Incoherent Phase unlocked

Time

What is Noisy Light?N

oisy

Lig

ht S

pect

rum

Frequency

Incoherent Phase unlocked

Time

Color locked!

What is Noisy Light?

Elet

ric F

ield

Stre

ngth

Time

Time

Beam

B

What is Noisy Light?

Elet

ric F

ield

Stre

ngth

Time

Elet

ric F

ield

Stre

ngth

Time

Time

Beam

B

Beam

B’

What is Noisy Light?

Elet

ric F

ield

Stre

ngth

Time

Elet

ric F

ield

Stre

ngth

Time

Time

tBeam

B

Beam

B’

What is Noisy Light?

Elet

ric F

ield

Stre

ngth

Time

Elet

ric F

ield

Stre

ngth

Time

Time

tBeam

B

Beam

B’

Compare t with tc

History

1983 1986 1996 1998 2014

Morita, Asaka, Hartmann develop the photon echo

Dugan develops Spectrally resolved CARS

Most noisy light papers published between 1986 and 1996. Many counter parts to short pulse methods.

FTC diagrams invented

Higher dimensional spectroscopy

Noisy light focused on application of CARS. Very few groups working with noisy light from 1996 on.

Exciton quantum beats

Foundations of Noisy Light

Optical coherence theory

Perturbation theory: Density operator

Noisy Light Spectroscopy

Nonlinear Spectroscopy

P= c ESignal

Material

Light field

Perturbation series approximation

P(t) = P(1) + P(2) + P(3) …

P(1) = c (1)E, P(2) = c (2)EE, P(3) = c (3)EEE

CARS

Coherent Anti-Stokes Raman Scattering

w1-w2= wR

wCARS= w1 +wRwR

w1

w1-w2

wCARS

Bichromophoric Model

a

b

Noisy light

P(t)(3)

P(s)(3)*

< >

Theoretical Challenges

•Complicated Mathematics•Complicated Physical Interpretation

Difficulty•The cw nature requires all field action permutations. The light is always on.•The proper treatment of the noise cross-correlates chromophores.

FTC Diagram Analysis

Set of intensity level terms

(pre-evaluated)

Set of evaluated intensity level

terms

Messy integration and algebra

Set of FTC diagrams

ConstructionRules

EvaluationRules

Physicshard hard

easy

FTC Diagram Analysis

a

b

P(t,{ti})

P(s,{si})

BB’

B’*B*

a b

a

b

P(t,{ti})

P(s,{si})

<BB’B’*B*> = <BB’*><B’B*> + <BB*><B’B’*>

FTC Diagram Analysis

a

b

P(t,{ti})

P(s,{si})

arrow segments: t-dependent correlation

line segments: t-independent correlation

Indirect Correlation

a

bt t

Indirect Correlation

a

bt t

Dynamics on a are probed!

I(2)CARS: Experiment

Monochromator

NarrowbandSource

BroadbandSource

Lens

Sample

Interferometer

t

B

B’

MI(2)CARS

ComputerCCD

•Signal is dispersed onto the CCD•Entire Spectrum is taken at each delay•2D data set: the Spectrogram

I(2)CARS: ExperimentGreat sensitivity to vibrational shifts and dephasing changes

Ring breathing mode of benzene in hexane

I(2)CARS: Data Processing

18000 18100 18200 18300 18400

-2

-1

0

1

2

BenzeneT22

0 200 400 600 800 1000 1200

0

25

50

75

100

125

150

BenzeneT22

100 200 300 400

0.2

0.4

0.6

0.8

Fourier

Transformation

X-Marginal

I(2)CARS: Hydrogen Bonding

17300 17400 17500 17600

-400

-200

0

200

400

Pyridine

17300 17400 17500 17600

-400

-200

0

200

400

Pyridine

17300 17400 17500 17600

-400

-200

0

200

400

ave x.45 pyr_water

FT

NeatPyridine

Pyridine/Water Xw= 0.55

I(2)CARS: Hydrogen Bonding

I(2)CARS: Hydrogen BondingNetwork model

Thermalized distribution model

Etc.

Fileti, E.E.; Countinho, K.; Malaspina, T.; Canuto, S. Phys. Rev. E. 2003, 67, 061504.

Halogen Bonding

Electropositves-hole

Test Charge

Electroneutral“ring”

Electronegative“belt”

I(2)CARS: Halogen BondingPyridine and C3F7I

0

0.5

1

1.5

2

2.5

3

3.5

4

900 920 940 960 980 1000 1020 1040 1060 1080 1100

Frequency (cm-1)

Norm

alize

d Intens

ity

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Neat

C6F13I and Pyridine

0

0.5

1

1.5

2

2.5

3

3.5

4

900 920 940 960 980 1000 1020 1040 1060 1080 1100Frequency (cm-1)

Norm

alize

d Intesit

y

Neat

0.1

0.2

0.3

0.4

0.5

0.6

0.7

.8

0.9

Exciton Quantum Beats

Exciton Quantum Beats

Future of Noisy Light

Spectroscopy• I(4)2DES Theory

• I(4)2DES Experiment• I(2)CARS Experiment

Information Processing• Dendritic Integration• Indirect correlation in

systems

Applied Mathematics• Group Theory• Graph Theory• Braid Theory

AcknowledgementsStudentsTheoryJahan DawlatyDan BiebighauserJohn GregioreDuffy Turner(M)

Kurt HaagIssac HeathCarena Daniels

Other Group MembersDr. Mark Gealy, Department of PhysicsDr. Eric Booth, Post-doctoral researcherDr. Haiyan Fan, Post-doctoral researcher

FundingNSF CAREER Grant CHE-0341087Henry Dreyfus Teacher/Scholar programConcordia Chemistry Research Fund

Method DevelopmentPye Phyo AungTanner Schulz(M)

Lindsay WeiselKrista CosertPerrie Cole(M)

Alex HarshBritt BergerZach JohnsonThao Ta

Hydrogen/HalogenbondingEric BergJeff Eliason(M)

Diane MolivaJason OlsonScott FlancherDanny Green

Exciton BeatsErika SutorBecca Hendrickson(M)

Meghan Knudtzon(M)

Dylan Howie(M)

Bobby Spoja