Efficient optical path folding by using multiple total internal reflections in a microcavity

TL;DR

This paper introduces a microcavity design that uses multiple total internal reflections along a star polygonal orbit to significantly extend the optical path length within a compact device, enhancing optical path efficiency.

Contribution

The authors demonstrate a novel microcavity structure that achieves a much longer optical path than the cavity size using stable total internal reflections, with experimental validation.

Findings

Achieved a 2.79 mm optical path in a 0.3 mm diameter cavity.

Fabricated a semiconductor device implementing the proposed design.

Validated the stability and efficiency of the optical path extension.

Abstract

We propose using an asymmetric resonant microcavity for the efficient generation of an optical path that is much longer than the diameter of the cavity. The path is formed along a star polygonal periodic orbit within the cavity, which is stable and confined by total internal reflection. We fabricated a semiconductor device based on this idea with an average diameter of 0.3 mm, and achieved a path length of 2.79 mm experimentally.