Generation of odd subharmonic Raman resonances from Stokes-anti-Stokes coupling

Abstract

The existence of odd Raman subharmonics in the nonlinear mixing of fields of frequencies ω_l and ω_s is examined in a nonperturbative way. It is shown that the coupling of Stokes and anti-Stokes processes at high pump powers produces odd subharmonics in nonlinearly generated signals. It is also shown that this coupling can lead to gain at the odd subharmonics. An effective Hamiltonian is used to discuss the coupling of Stokes-anti-Stokes processes. Numerical results showing the odd subharmonics are presented. The origin of odd subharmonics in terms of transitions among dressed states is also discussed.