Photocounting statistics of radiation propagating through passive and active random media

The photocounting statistics of radiation propagating through active, quadratic random media and through passive media are considered on the basis of a recently developed quantum dynamic theory. We show that the counting statistics for lossless random active media and those for passive weakly-inhomogeneous random media are similar, although there are some differences. The peak of the photocounting distribution shifts to lower count numbern and is found to broaden with increasing turbulence level, as in the case of passive media. In lossy active media, the shift of the peak to lowern is more pronounced, in pumped active media below threshold it is less so, and in pumped active media above threshold, there is a shift of the peak to highern as a consequence of self-radiation. Severe broadening occurs in this latter case. Photocounting statistics for special states of the incident field are also discussed.