Directional Emission from an Optical Microdisk Resonator with a Point Scatterer

TL;DR

This paper introduces a simple dielectric microdisk design with a point scatterer that achieves high-Q, highly directional light emission, combining experimental feasibility with analytical tractability.

Contribution

It proposes a novel microcavity design with a point scatterer to produce directional emission while maintaining high quality factors, supported by analytical methods.

Findings

Achieves highly directional emission with high Q-factors

Design is simple and experimentally feasible

Analytical approach based on Green's functions and extension theory

Abstract

We present a new design of dielectric microcavities supporting modes with large quality factors and highly directional light emission. The key idea is to place a point scatterer inside a dielectric circular microdisk. We show that, depending on the position and strength of the scatterer, this leads to strongly directional modes in various frequency regions while preserving the high Q-factors reminiscent of the whispering gallery modes of the microdisk without scatterer. The design is very appealing due to its simplicity, promising a cleaner experimental realisation than previously studied microcavity designs on the one hand and analytic tractability based on Green's function techniques and self-adjoint extension theory on the other.