1. Forecasting two-photon absorption based on one-photon properties
Nikolay Makarov,
Department of Physics, Montana State University
Mikhail Drobizhev, Zhiyong Suo, Aleks Rebane
E. Scott Tarter, Benjamin D. Reeves, Brenda Spangler
Fanqing Meng, Charles W. Spangler
Craig J. Wilson, Harry L. Anderson
Department of Physics, Montana State University, Bozeman, MT
Sensopath Technologies, Inc., Bozeman, MT
MPA Technologies, Inc., Bozeman, MT
Department of Chemistry, University of Oxford, Mansfield, Oxford, UK

2. Outline
Motivation
Experiments
Calculations
Conclusions

3. Motivation: Why to predict?l N H C l N C H N N C
Which one is better? Why?

4. Motivation: What can quantum chemistry do?
m, Em, m
C. Katan, S. Tretiak, M.H.V. Werts, A.J. Bain, R.J. Marsh, N. Leonczek, N. Nicolaou, E. Badaeva, O. Mongin, M. Blanchard-Desce,
“Two-photon transitions in quadrupolar and branched chromophores: experiment and theory”, J. Phys. Chem. B 2007, 111,

5. Experiments: Setup Jobin Yvon Triax 550 sample Laser system L2 USB
Coherent VERDI 6
4W CW 532nm L2
Coherent MIRA 900
0.5W 795nm 150fs
Wavelength control
Hamamatsu Streak Camera C5680
Coherent LEGEND
Regen. Amplifier
1.1W 1kHz 795nm 150fs
Intensity control
TOPAS-C
0.3W 1kHz 125fs
USB
Serial
Digital Oscilloscope
Ref. Channel DAQ
GPIB
CCD camera
control and DAQ PC
LabView
Filter
wheel
Corre-
lator
Ref. detector
FROG
OSA L1
Pulse characterization LN
CCD
sample
300
600
1200
l/mm-1 F1 M1
Jobin Yvon Triax 550
Perkin-Elmer Lambda900
Spectrophotometer
Perkin-Elmer LS 50B
Luminescence Spectrometer

6. Experimental Results 11 3 1 5 10 14 , M-1cm-1 s2, GM Frequency, cm-1
Wavelength, nm
s2, GM 11
, M-1cm-1
1.25104
2.5104
3.75104
5104 3
1104
2104
3104
4104
Frequency, cm-1 1 5 10 14

7. Second order perturbation theory:
Calculations: How to?
Second order perturbation theory: 1
Local field factors:
Lorentz
Onsager
Dipole moments:
Solvatochromic
shifts
Linear absorption,
fluorescence
Molecule density
Fluorescence anisotropy

8. Calculations: Results
100
200
300 7 2 11 6 9 1 8 5 4 3 12 10
2, GM
100
200
300
2, GM 11 2 12 10 5 4 1 6 9 7 8 3 14
R2
For molecule density (=1)
For anisotropy
2(a)
2(b) fL
0.8
3.3
1.4 fO
0.6
1.8
0.9

9. Conclusions Acknowledgements See poster for details
We show that the perturbation theory applied for two-level system quantitatively predicts the 2PA cross sections in dipolar molecules, provided that the necessary molecular parameters such as transition- and permanent dipole moments are independently measured.
In most cases, the discrepancy between theory and experiment was less than 20%, and always less than 50%. This is the first time that such direct quantitative correspondence is demonstrated for a wide range of dipolar molecules.
The overall significance of this work demonstrates a practical way how a set of relatively straightforward linear spectroscopic measurements can be used to study and predict nonlinear 2PA properties.
Acknowledgements
The work was supported by AFOSR.
See poster for details