A Phase-Sensitive Detection Method Using Diffractive Optics for Polarization-Selective Femtosecond Raman Spectroscopy

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Vol. 104; no. 24; pp. 5711 - 5715
• Main Authors: Khalil, M, Demirdöven, N, Golonzka, Oleg, Fecko, C. J, Tokmakoff, A
• Format: Journal Article
• Language: English
• Published: American Chemical Society 22.06.2000
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp994455q

A phase-sensitive detection method that uses two diffractive optics for femtosecond nonresonant Raman spectroscopy is demonstrated. One diffractive optic is used for generating the three input pulses for the third-order nonlinear experiment, and the second is used for recombining the signal with a passively phase-locked local oscillator derived from the probe pulse. This approach allows for phase-sensitive detection, direct phase calibration, control over all field polarizations, and removal of unwanted two-pulse signal contributions. Experiments on the intermolecular dynamics of CS2 and CH3CN demonstrate that the birefringent (in-quadrature) signal amplitude is significantly greater than the dichroic (in-phase) contribution. Polarization-selective measurements are used to project the isotropic birefringent response for CS2, which suppresses reorientational dynamics and allows interaction-induced effects to be observed.