Microcontroller-based locking in optics experiments

TL;DR

This paper introduces a cost-effective, microcontroller-based digital locking system for optical experiments, capable of stabilizing phases and cavity lengths without external modulations, offering a flexible alternative to traditional analog systems.

Contribution

The authors present a reconfigurable, software-programmable digital locking system that simplifies optical stabilization tasks and enhances automation in optical experiments.

Findings

Successfully stabilized optical cavities with different finesse levels

Achieved automatic relocking and sequential operation

Demonstrated compatibility with various optical locking algorithms

Abstract

Optics experiments critically require the stable and accurate locking of relative phases between light beams or the stabilization of Fabry-Perot cavity lengths. Here, we present a simple and inexpensive technique based on a stand-alone microcontroller unit to perform such tasks. Easily programmed in C language, this reconfigurable digital locking system also enables automatic relocking and sequential functioning. Different algorithms are detailed and applied to fringe locking and to low- and high-finesse optical cavity stabilization, without the need of external modulations or error signals. This technique can readily replace a number of analog locking systems advantageously in a variety of optical experiments.