Gas lasers with wave-chaotic resonators

TL;DR

This paper extends semiclassical laser theory to gas lasers with arbitrary-shaped open resonators, revealing unique mode coupling effects and spectral features in wave-chaotic resonators.

Contribution

It develops a generalized theory for gas lasers with complex resonator geometries, including the effects of Doppler shifts and wave chaos, and analyzes their spectral properties.

Findings

Linear coupling due to Doppler shift is negligible.

Intensity shows a local minimum at atomic transition frequency.

Minimum width scales with inhomogeneous linewidth.

Abstract

Semiclassical multimode laser theory is extended to gas lasers with open two-dimensional resonators of arbitrary shape. The Doppler frequency shift of the linear-gain coefficient leads to an additional linear coupling between the modes, which, however, is shown to be negligible. The nonlinear laser equations simplify in the special case of wave-chaotic resonators. In the single-mode regime, the intensity of a chaotic laser, as a function of the mode frequency, displays a local minimum at the frequency of the atomic transition. The width of the minimum scales with the inhomogeneous linewidth, in contrast to the Lamb dip in uniaxial resonators whose width is given by the homogeneous linewidth.