Simple, highly-stable transfer cavity for laser stabilization based on a carbon-fiber reinforced polymer spacer

TL;DR

This paper presents a cost-effective, highly stable Fabry-Perot cavity using a carbon-fiber reinforced polymer spacer, achieving low thermal expansion and stable laser frequency control suitable for quantum science applications.

Contribution

The design introduces an inexpensive, highly stable cavity with ultra-low thermal expansion using a common polymer spacer, enhancing laser stabilization methods.

Findings

Cavity exhibits a thermal expansion coefficient of 1.6×10⁻⁶ K⁻¹.

Frequency excursions are below 50 MHz over a day at room temperature.

The system is suitable for transferring laser stability and linewidth reduction.

Abstract

We describe the design and operation of a high-stability Fabry-Perot cavity, for laser stabilization in cavity quantum-electrodynamics experiments. Our design is based on an inexpensive and readily available uniaxial carbon-fiber reinforced polymer tube spacer, featuring an ultra-low thermal expansion coefficient. As a result, our $136\mathrm{mm}$-long cavity, which has a finesse of ${5160}$, shows a coefficient of thermal expansion of $1.6 \times 10^{-6}~\mathrm{K}^{-1}$. Enclosing it in a hermetic chamber at room-pressure and using a simple temperature stabilization, we observe absolute frequency excursions over a full day below $50~\mathrm{MHz}$ for a laser operating at $446.785\mathrm{THz}$. The frequency stability is limited by the imperfect thermal isolation from the environment and can be corrected using a built-in piezo-electric actuator. In addition, we discuss a different variant of this design and identify future improvements. Our system provides a cost-effective and robust solution for transferring laser stability over different wavelengths, as well as for linewidth reduction or spectral filtering of CW laser sources for applications in quantum science.