Off-resonant coherent hyper-Raman scattering spectroscopy

Abstract

A theoretical description of the off-resonant coherent hyper-Raman scattering spectroscopy is presented. By considering two pump fields whose frequencies and corresponding wave vectors are ω1, ω2(=2ω1), k1, and k2, respectively, the effective Hamiltonian is derived to show that the spatial transient grating can be created by the third-order interaction with the pump fields. A delayed probe field with frequency of ω1 and wave vector of k1 is scattered by the spatial transient grating to produce the macroscopic polarization with wave vector 4k1−k2. The expressions for the measured signals by homodyne and heterodyne method are derived and compared with that of the spontaneous hyper-Raman scattering signal.