On limitation of quality factor of single mode resonators with finite size

TL;DR

This paper investigates the limitations on the quality factor of finite-sized single-mode resonators, demonstrating that cavity shape engineering cannot significantly improve their radiative loss limits.

Contribution

It provides a comparative analysis of whispering gallery and Fabry-Perot cavities, revealing fundamental constraints on Q-factor enhancement through cavity design.

Findings

Similar properties of different cavity types despite different loss mechanisms

Cavity shape engineering does not significantly reduce radiative losses

Identification of parameter sets for single-mode operation in high-Q cavities

Abstract

Using realistic numerical models we analyze radiative loss of bound and unbound modes of specially designed high-Q whispering gallery and Fabry-Perot cavities of similar size and shape, and find a set of parameters when they can be treated as single mode structures. We show that these cavities have similar properties in spite of their different loss mechanisms. The cavity morphology engineering does not lead to reduction of the resonator quality factor.