Development of non-magnetic VCSEL module for compact atomic magnetometer

The integrated Vertical-Cavity Surface-Emitting Lasers (VCSELs) modules have been widely researched and manufactured accompanying with the rapid development of compact atomic magnetometers, atomic gyroscopes, atomic clocks, and the other atomic sensors. For atomic magnetometers operating in the Spin-Exchange Relaxation-Free (SERF) regime, the vapor cell should be heated to a high temperature, which may cause the built-in laser chip over-heated and module structural or optical component deformation, lowering the performance of the built-in laser module. Meanwhile, due to the space constraints, the laser module needs to achieve a large collimation beam diameter and the non-magnetic structure should be optimized to have high temperature tolerance and stable thermal dissipation. In this study, a compact non-magnetic VCSEL module is developed based on the non-magnetic structure with the abilities of optical path alignment, beam collimation, and polarization conversion. Compared with the common TO-can packaging, the proposed VCSEL module achieved low residual magnetic field generated. And the entire volume is less than 1 cm3 with the collimating beam diameter of 2 mm. The experiment evaluation result shows that the laser module could work stably in high temperature with stable thermal dissipation and sufficient thermal margin (60±10℃) for precise wavelength tuning and maintain optical performance and structural for meeting the demand of pump laser in the SERF atomic magnetometers.