Theory of light fluctuation filtering in twophoton absorption process by multiple second harmonic generation. I  Basic equations: Classical description
Abstract
Multiple second harmonic generation in which the generated second harmonic radiation is filtered out at each stage is studied in this paper. Both classical and quantum equations describing this process are derived, and it is shown that multiple second harmonic generation in thin nonlinear plates acts in the same way as the twophoton absorption process. A closed classical solution for stochastic photon number is found and, for chaotic input radiation, the mean photon number and the mean quadratic fluctuation (variance) of the integrated intensity in the fundamental radiation are calculated. It is shown that the variance of the intensity systematically decreases in the course of the process and, thus, the statistical distribution of the fundamental radiation approaches the coherent state from the point of view of classical theory.
 Publication:

Optical and Quantum Electronics (ISSN 03068919
 Pub Date:
 September 1984
 Bibcode:
 1984OptQE..16..445C
 Keywords:

 Harmonic Generations;
 Multiphoton Absorption;
 Nonlinear Optics;
 Optical Filters;
 Variance (Statistics);
 Electromagnetic Interactions;
 Field Theory (Physics);
 Fluctuation Theory;
 Optical Data Processing;
 Phase Matching;
 Quantum Theory;
 Wave Interaction;
 Optics