Design of a highly reliable and low-cost optical bench for laser cooling

Abstract

High-reliability optical systems play an essential role in the wide application of precision cold atom quantum sensors such as cold atom clocks, cold atomic magnetometers and cold atom interferometers. Achieving thermal stability performance is especially critical because the long-term performance of a cold atom system is often ultimately limited by the thermal stability of the optical system. In this paper, we find that the material consistency of the parts on the optical bench is more important for the thermal stability of the optical system than reducing the expansion coefficient of the parts. On several optical benches with the same architecture but different fiber coupler material combinations, the minimum fiber coupling efficiency change reached approximately 3.5% in the variation range of ambient temperature from 8℃ to 43℃, and the coupling efficiency change was less than 0.3% before and after thermal cycling. In addition, a full-function optical bench for rubidium atom laser cooling was developed based on the assembly procedure of the test optical bench. In the multiple output fibers on the bench, the maximal coupling efficiency variation was less than 19% in the range of 8℃∼43℃, and the output laser power change was less than 2% in the bench before and after thermal cycling.