Photon statistics of a random laser
Abstract
A general relationship is presented between the statistics of thermal radiation from a random medium and its scattering matrix S. Familiar results for black-body radiation are recovered in the limit S to 0. The mean photocount is proportional to the trace of 1-SS^dagger, in accordance with Kirchhoff's law relating emissivity and absorptivity. Higher moments of the photocount distribution are related to traces of powers of 1-SS^dagger, a generalization of Kirchhoff's law. The theory can be applied to a random amplifying medium (or "random laser") below the laser threshold, by evaluating the Bose-Einstein function at a negative temperature. Anomalously large fluctuations are predicted in the photocount upon approaching the laser threshold, as a consequence of overlapping cavity modes with a broad distribution of spectral widths.
Cite
@article{arxiv.quant-ph/9808066,
title = {Photon statistics of a random laser},
author = {C. W. J. Beenakker},
journal= {arXiv preprint arXiv:quant-ph/9808066},
year = {2013}
}
Comments
26 pages, including 9 figures