Chaotic microcavity laser with high quality factor and unidirectional output

Abstract

We demonstrate a chaotic microcavity laser whose quality is comparable to typical nonchaotic microcavity lasers, yet it has the unique characteristic of unidirectional output. The cavity shape is a disk with the boundary defined by a curve called lima\ifmmode \mbox{\c{c}}\else \c{c}\fi{}on of Pascal. For a lasing mode of volume less than $0.2\text{ }\ensuremath{\mu}{\text{m}}^{3}$, the measured quality factor is $23\text{ }000$. The record-high quality and small modal volume result in extremely low-lasing threshold. The spontaneous emission coupling efficiency is approximately 6% and is the reported value for a chaotic microcavity laser. All the lasing modes have one output beam in the same direction with a divergence angle less than $40\ifmmode^\circ\else\textdegree\fi{}$. This universal directionality is determined by the chaotic ray dynamics in the open cavity.