Ultra-compact reference ULE cavity

TL;DR

This paper reports the development and experimental characterization of an ultra-compact, stable laser system based on a novel 25 mm pyramidal Fabry-Perot cavity with crystalline coatings, achieving low frequency instability.

Contribution

It introduces a new ultra-compact cavity design with high stability and provides initial measurements of its thermal, vibration sensitivities, and frequency stability.

Findings

Measured fractional frequency instability of 7.5×10⁻¹⁵ at 1 second

Demonstrated cavity fits within 30 L volume

Assessed thermal and vibration sensitivities of the cavity

Abstract

We present a first experimental characterization of our ultra-compact, ultra-stable laser. The heart of the apparatus is an original Fabry-Perot cavity with a 25 mm length and a pyramidal geometry, equipped with highly-reflective crystalline coatings. The cavity, along with its vacuum chamber and optical setup, fits inside a 30 L volume. We have measured the cavity thermal and vibration sensitivities, and present a first estimation of the cavity fractional frequency instability at $\sigma_y(1\rm{s})=7.5{\times}10^{-15}$.