Quantum Statistics and Coherence of Nonlinear Optical Processes

Jan Peřina

R. Tanaś

Daniel F. Walls

S. Naguleswaran, G E Stedman

Results following from time-reversal symmetry are developed for those nonlinear optical processes where a statistical average is required. These generalize previous analyses by removing the electric dipole approximation and allowing for intermediate resonances. For example, Onsager relations for self-conjugate nonlinear optical processes (when input and output photons form degenerate pairs) are derived and associated reversality relations generalized. In the nonresonant limit magnetic-dipole but not electric-quadrupole terms in coherent processes are suppressed. For general processes purely electric dipole contributions to natural optical activity are possible when intermediate resonances are present.

Jan Peřina

Jan Peřina, J. Křepelka

Compared with earlier investigations we follow a way of arising singularities in quasidistributions as related to nonclassical photocount and wave statistics for nonlinear optical processes described by Gaussian statistics, also from the point of view of testing functions. Further we illustrate a process of regularization of singular quasidistributions so that regularized quasidistributions can provide measurable quantities. Results obtained can be applied to optical down-conversion as well as to Raman scattering provided that classical strong coherent pumping fields are used.