Waves and rays in plano-concave laser cavities, Part~II: a semiclassical approach

TL;DR

This paper develops a semi-classical approach to analyze the spectrum of plano-concave laser cavities, linking wave optics and geometrical optics through periodic orbits, with experimental validation using micro-lasers.

Contribution

It introduces a trace formula for the spectrum based on axial periodic orbits in plano-concave cavities, extending semi-classical methods to laser cavity analysis.

Findings

Spectrum determined by axial periodic orbit and its repetitions

Experimental validation with micro-lasers supports theoretical predictions

Methods applicable to various wave systems beyond laser cavities

Abstract

This second paper on the Fabry-Perot cavity presents a semi-classical approach, which means that we consider the transition from wave optics to geometrical optics. The basic concepts are the periodic orbits and their stability. For the plano-concave Fabry-Perot cavity in the paraxial approximation, the derivation of the trace formula demonstrates that the spectrum is based only on the axial periodic orbit and its repetitions. Experiments with micro-lasers illustrate the relation to periodic orbits. The methods presented in this paper are not limited to laser cavities and can be applied to a large range of wave systems.