A laser system for cooling strontium atoms in a new Rydberg atom-array experiment

Abstract

In this work we report on the construction of a laser system for laser cooling of strontium atoms. This lays the foundation to a new cold atoms experiment which aims to simulate lattice gauge theories with Rydberg decorated tweezer arrays. The developed laser system uses the 1S0 ↔ 1P1 transition of strontium-88 at 461 nm. We focus on the master laser frequency stabilisation through an active spectroscopic feedback on a vapour cell. Therein, the high vacuum regime has been restored and new strontium has been introduced as part of this thesis project. We explore Doppler-free spectroscopy through saturated absorption, specifically locking the master laser on a modulation transfer spectroscopy signal. In addition, we address the need for specific frequency control in the different cooling stages of the experiment by implementing the use of acousto-optical modulators. Finally, we tackle the required optical power amplification by assembling and characterising one of the slave lasers that will be used to that end, ensuring thereby the suitability of the laser system for its purpose.