Filament-based stimulated Raman spectroscopy

摘要

A new multiplexed stimulated Raman spectroscopic technique encompassing a single-shot spectral measurement range of over 3900 cm~(-1) is presented. Impulsive excitation of all Raman active vibrational modes present in a medium is achieved by self-compression of a laser pulse undergoing filamentation in air, creating coherent vibrational wave-packets. These wave-packets create a macroscopic polarization of the medium that imparts sidebands on a delayed narrowband probe pulse. The background-free measurement of impulsively excited Raman modes in gas-phase N_2, O_2, H_2, CO_2, toluene, ammonia, and chloroform with a spectral resolution of 25 cm~(-1) is presented.