Microwave whispering gallery resonator for efficient optical up-conversion

TL;DR

This paper presents a theoretical and experimental study of a microwave whispering gallery resonator that achieves efficient optical up-conversion by optimizing phase matching and field overlap, enabling near-unity conversion efficiency.

Contribution

It introduces a novel resonator geometry that ensures phase matching and maximizes field overlap for efficient microwave-to-optical conversion at any sub-THz frequency.

Findings

Resonator geometry enables phase matching at desired frequencies.

Maximized field overlap enhances conversion efficiency.

Unity quantum efficiency predicted with feasible parameters.

Abstract

Conversion of microwave radiation into the optical range has been predicted to reach unity quantum efficiency in whispering gallery resonators made from an optically nonlinear crystal and supporting microwave and optical modes simultaneously. In this work we theoretically explore and experimentally demonstrate a resonator geometry that can provide the required phase matching for such a conversion at any desired frequency in the sub-THz range. We show that such a ring-shaped resonator not only allows for the phase matching, but also maximizes the overlap of the interacting fields. As a result, unity-efficient conversion is expected in a resonator with feasible parameters.