New high-resolution phonon spectroscopy using impulsive stimulated Brillouin scattering

Abstract

Impulsive stimulated Brillouin scattering is applied to a new high‐resolution phonon spectroscopy, where phonons created by two crossing pump pulses are observed using diffraction of a cw probe light in both time and frequency domains. In time domain, real‐time behavior can be detected sensitively using a digital oscilloscope, while in frequency domain, measurements with high resolution are attainable by means of a spherical Fabry–Perot interferometer. Several examples of the measurements on liquid samples are demonstrated for clarifying various aspects of the phonon generation by the present method: the mechanism of the generation under pulsed light irradiation, the propagation of the generated phonon, the resonance excitation, and the interference with the other nonlinear optical processes. The relation with the ordinary light scattering is also discussed.