Origin of emission from square-shaped organic microlasers

TL;DR

This paper investigates the emission mechanisms of square-shaped organic microlasers through combined experimental and theoretical approaches, revealing how their geometry influences far-field emission patterns and mode behaviors.

Contribution

It introduces a semiclassical model that accurately predicts emission patterns and identifies lasing modes in square-shaped organic microlasers, linking ray dynamics with wave phenomena.

Findings

Far-field emission is concentrated along cavity side walls.

The semiclassical model matches experimental emission features.

Diffraction and finite size effects are crucial for understanding emission.

Abstract

The emission from open cavities with non-integrable features remains a challenging problem of practical as well as fundamental relevance. Square-shaped dielectric microcavities provide a favorable case study with generic implications for other polygonal resonators. We report on a joint experimental and theoretical study of square-shaped organic microlasers exhibiting a far-field emission that is strongly concentrated in the directions parallel to the side walls of the cavity. A semiclassical model for the far-field distributions is developed that is in agreement with even fine features of the experimental findings. Comparison of the model calculations with the experimental data allows the precise identification of the lasing modes and their emission mechanisms, providing strong support for a physically intuitive ray-dynamical interpretation. Special attention is paid to the role of diffraction and the finite side length.