Theory of resonant Raman scattering of intense optical waves

Abstract

The theory of resonant Raman scattering in the presence of intense incident and scattered light waves has been developed, using the quantum-mechanical master-equation approach. When the optical matrix elements -d_ij. E_rad be tween the resonant intermediate state and the initial and final states of the atomic system are larger than the relevant relaxation frequencies 1/T_ij shown that instead of the usual power broadening and shift of the Stokes or anti-Stokes line, each line can split into as many as five or seven lines, depending upon whether both the fields are exactly at resonance or otherwise. One finds that many of the qualitative features of the resonant spectra can be obtained from the solution of the eigenvalue problem of the resonant three-level Hamiltonian involving the intermediate state |1> and the initial and final states |3> and |2>. But, to find details of the shape of the spectrum, we have to include both the non-radiative and radiative decay terms in the master equation, and then solve for the two-time system correlation functions. Numerical results for the resulting spectrum are presented for different cases. This shows how one can obtain system parameters more easily by analysing the high-field spectrum. In intense fields, the stimulated and spontaneous spectra are found to have different structures.