Temperature-insensitive tunable and stable Fabry-Perot cavity for atomic physics

TL;DR

This paper presents a temperature-insensitive, tunable Fabry-Perot cavity that maintains high stability without external feedback, benefiting atomic physics experiments and quantum optics.

Contribution

A novel piezoelectrically-tunable cavity with thermal expansion cancellation at around 5°C, reducing reliance on external stabilization systems.

Findings

Achieves fractional frequency instability of 4×10⁻¹³ at 1s

Eliminates need for external stabilization in many experiments

Suitable for ultra-stable lasers and cavity QED applications

Abstract

Optical Fabry-Perot cavities are crucial tools for metrology experiments, where they achieve extreme length stability, and for some atomic physics experiments, where tunability to atomic transitions enables atom-light interactions. However, achieving both frequency stability and tunability in a single cavity has remained a challenge, forcing metrology experiments exploiting atom-cavity interactions to rely on external active feedback systems to stabilize the length of the cavity. Here, we describe a piezoelectrically-tunable cavity with a cancellation of the coefficient of thermal expansion at around $5^\circ\mathrm{C}$, achieving fractional frequency instabilities at the $4\times 10^{-13}$ level for 1~s integration time. This advance eliminates the need for external stabilization in many atom-cavity experiments, making this design ideal for applications such as ultra-stable superradiant lasers and other cavity quantum electrodynamics experiments.