Noisy Light Spectroscopy Darin J. Ulness Department of Chemistry Concordia 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 Noisy Light Spectrum Frequency Time resolution on the order of the correlation time,  c

What is Noisy Light? Ultrashort pulse Short Pulse Spectrum Frequency Time resolution on the order of the pulse width Coherent Phase locked Time Broadband Phase incoherent Quasi continuous wave

What is Noisy Light? Noisy Light Spectrum Frequency Incoherent Phase unlocked Time

What is Noisy Light? Noisy Light Spectrum Frequency Incoherent Phase unlocked Time Color locked!

What is Noisy Light? Time Beam B

What is Noisy Light? Time Beam B Beam B’

What is Noisy Light? Time  Beam B Beam B’

What is Noisy Light? Time  Beam B Beam B’ Compare  with  c

History Morita, Asaka, Hartmann develop the photon echo Dugan develops Spectrally resolved CARS Most noisy light papers published between 1986 and 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=  E Signal Material Light field Perturbation series approximation P(t) = P (1) + P (2) + P (3) … P (1) =  (1) E, P (2) =  (2) EE, P (3) =  (3) EEE

CARS Coherent Anti-Stokes Raman Scattering  1 -  2 =  R  CARS =  1 +  R RR 11 11  2  CARS

Bichromophoric Model   Noisy light P(t)P(t) (3) P(s)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 Construction Rules Evaluation Rules Physics hard easy

FTC Diagram Analysis   P(t,{t i }) P(s,{s i }) B B’ B’* B*     P(t,{t i }) P(s,{s i }) = +

FTC Diagram Analysis   P(t,{t i }) P(s,{s i }) arrow segments:  -dependent correlation line segments:  -independent correlation

Indirect Correlation   

   Dynamics on  are probed!

I (2) CARS: Experiment Monochromator Narrowband Source Broadband Source Lens Sample Interferometer t B B’ M I (2) CARS Computer CCD Signal is dispersed onto the CCD Entire Spectrum is taken at each delay 2D data set: the Spectrogram

I (2) CARS: Experiment Great sensitivity to vibrational shifts and dephasing changes Ring breathing mode of benzene in hexane

I (2) CARS: Data Processing Fourier Transformation X-Marginal

I (2) CARS: Hydrogen Bonding FT Neat Pyridine Pyridine/ Water X w = 0.55

I (2) CARS: Hydrogen Bonding

Network model Thermalized distribution model Etc. Fileti, E.E.; Countinho, K.; Malaspina, T.; Canuto, S. Phys. Rev. E. 2003, 67,

Halogen Bonding Electropositve  -hole Test Charge Electroneutral “ring” Electronegative “belt”

I (2) CARS: Halogen Bonding

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

Acknowledgements Students Theory Jahan Dawlaty Dan Biebighauser John Gregiore Duffy Turner (M) Kurt Haag Issac Heath Carena Daniels Other Group Members Dr. Mark Gealy, Department of Physics Dr. Eric Booth, Post-doctoral researcher Dr. Haiyan Fan, Post-doctoral researcher Funding NSF CAREER Grant CHE Henry Dreyfus Teacher/Scholar program Concordia Chemistry Research Fund Method Development Pye Phyo Aung Tanner Schulz (M) Lindsay Weisel Krista Cosert Perrie Cole (M) Alex Harsh Britt Berger Zach Johnson Thao Ta Hydrogen/Halogen bonding Eric Berg Jeff Eliason (M) Diane Moliva Jason Olson Scott Flancher Danny Green Exciton Beats Erika Sutor Becca Hendrickson (M) Meghan Knudtzon (M) Dylan Howie (M) Bobby Spoja