title: Generalized Kramers-Heisenberg expressions for stimulated Raman scattering and two-photon absorption.
abstract: The frequency-domain pump-probe signal of a material system interacting with two quantum modes of the radiation field is recast in terms of products of scattering amplitudes (T matrix elements) rather than the third-order susceptibility Im chi((3)). The resulting expression offers a more intuitive physical picture for the optical process compared with the semiclassical approach which treats the radiation field as classical. It can be derived and interpreted using closed-time-path-loop diagrams which represent the joint state of the matter and the field for each contribution to the signal. The signal has two components representing stimulated Raman scattering omega(1) - omega(2) and two-photon absorption omega(1) + omega(2) two-photon resonances. Both are expressed as nonequi-librium steady-state photon and matter fluxes, as is common in the description of dissipative processes in open quantum systems.
authors.affiliation: Department of Chemistry, University of California, Irvine, California 92697, USA.
authors.forename: Oleksiy
authors.initials: O
authors.lastname: Roslyak
authors.forename: Christoph A
authors.initials: CA
authors.lastname: Marx
authors.forename: Shaul
authors.initials: S
authors.lastname: Mukamel