Versatile Digital GHz Phase Lock for External Cavity Diode Lasers

TL;DR

This paper introduces a versatile, cost-effective digital phase lock system for external cavity diode lasers, capable of locking frequencies from sub-MHz to 12 GHz, suitable for atomic physics experiments involving alkali metals.

Contribution

The paper presents a novel all-digital phase lock method that eliminates the need for microwave-range references and extends locking capabilities up to 12 GHz.

Findings

Achieves phase locking from sub-MHz to 12 GHz.

No microwave reference input required.

Universal for alkali metal hyperfine splittings.

Abstract

We present a versatile, inexpensive and simple optical phase lock for applications in atomic physics experiments. Thanks to all-digital phase detection and implementation of beat frequency pre-scaling, the apparatus requires no microwave-range reference input, and permits phase locking at frequency differences ranging from sub-MHz to 7 GHz (and with minor extension, to 12 GHz). The locking range thus covers ground state hyperfine splittings of all alkali metals, which makes this system a universal tool for many experiments on coherent interaction between light and atoms.