A new form of frequency-selective all-optical heterodyning at the difference frequency of two modulated laser beams, related to stochastic resonance, is reported. A noise-induced enhancement of the heterodyne signal and of the signal-to-noise ratio has been predicted and observed in an all-optical bistable system for the beams at different wavelengths.
Copyright 1995 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters, 67 (3), 1995 and may be found at http://scitation.aip.org/content/aip/journal/apl/67/3/10.1063/1.115427