Photon statistics of various radiation sources

Recent successful experimental demonstrations of the self-amplified spontaneous emission (SASE) in the infra-red region of the spectrum and project proposals for the production of XUV/X-ray SASE radiation have revitalized the interest in the statistical properties of FEL radiation. In this paper, after a review of photon statistics is given, those from various types of radiation including non-classical light are compared. Predicted photon statistics (or lack thereof) from a FEL oscillator, an amplifier, coherent spontaneous emission (CSE), SASE and high-gain harmonic generation (HGHG) are summarized. Different schemes of experimental methods to measure photon statistics are examined, and the experiment carried out at the National Synchroton Light Source (NSLS) to measure the photon statistics of wiggler spontaneous emission is described.