Design of a multi-laser module for optical pumping in compact atomic gyroscopes

Abstract

In the compact atomic gyroscopes, the vertical-cavity surface-emitting laser (VCSEL) is usually utilized as the laser source. However, the power of VCSEL is not sufficient to polarize the nuclear spin efficiently. To solve this problem, we put forward a multi-laser module design for optical pumping in compact atomic gyroscopes. In this module, several lasers are integrated in one module and utilized together for pumping. We fabricated and tested a laser module with two VCSELs for demonstration. First of all, the beam collimation system is simulated, and it is concluded that the two lasers can be integrated on the same micro-heater and collimated by the same lens. This is proved experimentally by beam profile measurement. Furthermore, the polarization distribution is simulated and investigated, and the results indicate that the polarization and its homogeneity can be increased significantly when pumping with two lasers. Finally, the nuclear polarization is measured experimentally, and it is demonstrated that the nuclear polarization when pumping with two 1 mW lasers is increased from 3.71% to 5.52%, and the proportion of the increase is more than 48% compared to that when pumping with a single 1 mW laser. These results prove the feasibility of the design, and this multi-laser pumped regime provides new inspirations for the development of compact atomic gyroscopes.