Femtosecond resonance enhanced CARS for background-free detection of organic molecules

Abstract

We study the coherent excitation profile (CEP) of resonance enhanced femtosecond CARS in a model system zinc phthalocyanine in a polymer film host as a prospective technique for detection and identification of molecular species in ambient environments. A new method of suppressing the non-resonant FWM background is demonstrated. Transform theory is applied to calculate CEP based on the absorption spectrum, and good agreement between theory and experiment is obtained.

Acknowledgements

This work was supported by AFOSR grant F49620-01-1-0406. I. Tehver thanks Estonian Science Foundation for support (Grant No. 5549). The authors thank J. Reintjes for valuable discussions concerning this paper.