Abstract

The univariate and bivariate intensity statistics of amplified spontaneous emission (ASE) from continuously excited HeNe and HeXe gas discharges have been measured for the purpose of characterizing the dependence of ASE fluctuations on gain length and degree of homogeneous broadening. Comparison with theoretical results from a model for intensity fluctuations in heavily saturated multimode systems confirms that increasing the homogeneous broadening lowers the number of competing "modes" in the system. Intrinsic to this simple coupled-intensity model are unique combinations of cumulants that are independent of the number of modes and the strength of their coupling. These combinations have been measured, and they are independent of the degree of homogeneous broadening and are constant as the discharge length is increased. The normalized cumulants and cross-correlations for coprapogating and counterpropagating orthogonal, circularly polarized beams in a HeXe homogeneously broadened medium are consistently smaller in magnitude than those for orthogonal, linearly polarized beams. Comparison of results for neon and xenon discharges will distinguish whether this is the result of back-reflections or is a property of the counterpropagating beams quasiresonant with these noble-gas transitions, which differ in their upper- and lowerstate angular momenta.

© 1990 Optical Society of America