Ray picture and ray-wave correspondence in triangular microlasers

TL;DR

This paper uses ray-optical methods to analyze emission patterns in triangular dielectric microlasers, extending geometrical optics with intensity amplification, and finds good agreement with wave simulations and experiments.

Contribution

It introduces a novel approach focusing on maximum intensity trajectories, not just periodic orbits, to explain microlaser emission patterns.

Findings

Maximum intensity trajectories predict emission patterns accurately.

Inclusion of intensity amplification improves geometrical optics models.

Results align with electromagnetic simulations and experimental data.

Abstract

We apply ray-optical methods to dielectric optical microcavities in the shape of triangles made of low refractive index material. We find ray trajectories that maximize the intensity inside the cavity to determine the far-field emission characteristics and to complement the concept of the unstable manifold applicable to chaotic microlasers. As these maximum intensity trajectories need not to be periodic, we suggest that they provide a more general explanation for emission patterns of microlasers than short periodic orbits. Further, the geometrical optics description is extended by the inclusion of intensity amplification along the optical path to achieve a better description of active, lasing cavities. Far-field emission patterns of equilateral triangle cavities obtained in this way agree well with our full electromagnetic wave simulations and with previously reported experimental results.