Cavity-enhanced Raman scattering for in situ alignment and characterization of solid-state microcavities

TL;DR

This paper demonstrates cavity-enhanced Raman scattering in a miniaturized tunable Fabry-Pérot cavity with a diamond membrane, achieving significant signal amplification via the Purcell effect, enabling in situ cavity mode characterization and improved emitter outcoupling.

Contribution

It introduces a novel cavity-enhanced Raman technique for in situ alignment and characterization of solid-state microcavities, leveraging a simple optical setup and strong signal amplification.

Findings

Raman intensity is enhanced 58.8-fold by the cavity.

Cavity-enhanced Raman can be used as a narrowband, high-intensity internal light source.

The method facilitates in situ mode-matching and dispersion measurement of cavity modes.

Abstract

We report cavity-enhanced Raman scattering from a single-crystal diamond membrane embedded in a highly miniaturized fully-tunable Fabry-P\'{e}rot cavity. The Raman intensity is enhanced 58.8-fold compared to the corresponding confocal measurement. The strong signal amplification results from the Purcell effect. We show that the cavity-enhanced Raman scattering can be harnessed as a narrowband, high-intensity, internal light-source. The Raman process can be triggered in a simple way by using an optical excitation frequency outside the cavity stopband and is independent of the lateral positioning of the cavity mode with respect to the diamond membrane. The strong Raman signal emerging from the cavity output facilitates in situ mode-matching of the cavity mode to single-mode collection optics; it also represents a simple way of measuring the dispersion and spatial intensity-profile of the cavity modes. The optimization of the cavity performance via the strong Raman process is extremely helpful in achieving efficient cavity-outcoupling of the relatively weak emission of single color-centers such as nitrogen-vacancy centers in diamond or rare-earth ions in crystalline hosts with low emitter density.