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MO: Fachverband Molekülphysik

MO 1: Vibrational Spectroscopy

MO 1.2: Talk

Monday, March 12, 2012, 11:00–11:15, V38.03

The full characterization of the third-order nonlinear susceptibility using single-beam-CARS — •Alexander Wipfler, Jean Rehbinder, Tiago Buckup, and Marcus Motzkus — Physikalisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, D-69120 Heidelberg, Germany

Single-beam-CARS setups circumvent the experimental challenge of superposing two laser pulses in space and time. However the information on the nonlinear susceptibility is often poor compared to conventional CARS and spontaneous Raman measurements. We present a method that allows for the full characterization of the susceptibility by introducing a phase gate in the excitation spectrum. The phase of this gate is subsequently set to four different values which makes a double quadrature spectral interferometry (DQSI) operation possible. This operation delivers amplitude and phase of the third-order nonlinear susceptibility. The theoretical background including simulations of the scheme and experimental results on toluene will be presented. As amplitude and phase are obtained, the information on the susceptibility gained with our method exceeds the one from conventional CARS experiments and even spontaneous Raman measurements.