Transient four-wave and six-wave mixing with the excitation of subharmonic Raman resonances

Abstract

Molecular polarizability theory with the inclusion of the second-hyperpolarizability coefficient is used to study the transient generation of four-wave- and six-wave-mixing signals when a system interacts with laser and Stokes pulses of frequencies ω _l and ω _S lying in the region of the subharmonic Raman resonance ω_l- ω_S≊ ω_R/2. The dynamical equations for various fields and amplitudes of the Raman and the subharmonic mode are derived and integrated numerically to obtain the detailed characteristics, such as pulse width, pulse center, ringing, etc., of the generated signals. The effect of the chirp in the incident pump pulse is also studied.