A compact ultranarrow high-power laser system for experiments with 578nm Ytterbium clock transition

TL;DR

This paper reports the development of a compact, high-power laser system at 578 nm for Ytterbium clock transition experiments, achieving narrow linewidth and stable operation suitable for precision measurements.

Contribution

The authors present a novel laser system combining frequency doubling and advanced stabilization techniques for ultranarrow linewidth at 578 nm.

Findings

Achieved up to 60 mW of 578 nm light from a quantum dot laser.

Locked the laser to a stabilized cavity with 500 kHz bandwidth.

Observed the Ytterbium clock transition with <50 Hz linewidth over 5 minutes.

Abstract

In this paper we present the realization of a compact, high-power laser system able to excite the Ytterbium clock transition at 578 nm. Starting from an external-cavity laser based on a quantum dot chip at 1156 nm with an intra-cavity electro-optic modulator, we were able to obtain up to 60 mW of visible light at 578 nm via frequency doubling. The laser is locked with a 500 kHz bandwidth to a ultra-low-expansion glass cavity stabilized at its zero coefficient of thermal expansion temperature through an original thermal insulation and correction system. This laser allowed the observation of the clock transition in fermionic $^{173}$Yb with a < 50 Hz linewidth over 5 minutes, limited only by a residual frequency drift of some 0.1 Hz/s.