Hao Jian, Ke Hong-Liang, Yang Zhai-Yue, Han Bang-Cheng
Zhejiang Lab, Research Center for Quantum Sensing, Hangzhou 310000, China.
Hangzhou Innovation Institute, Beihang University, Hangzhou 310000, China.
Sensors (Basel). 2021 Apr 23;21(9):2982. doi: 10.3390/s21092982.
In order to improve the precision and beam quality of a pump laser for a spin exchange relaxation free inertial measurement device, we applied one scheme to achieve the square wave modulation and power stability control of the pump laser and another one to obtain the uniform intensity distribution of the laser beam, in which the acousto-optic modulator (AOM) and proportion integration differentiation (PID) controller were used to achieve the former, and the freeform surface lens was designed and optimized to achieve the latter based on the TracePro software. In experiments, the first-order diffraction light beam coming through the AOM had a spot size of about 1.1×0.7 mm, and a spherical vapor cell with a radius of 7 mm was placed behind the freeform surface lens. Results show that the uniformity of the reshaped intensity distribution is higher than 90% within the target area with a radius of 7 mm both in the simulation and the experiment, which ensure that the uniform laser beam covers the area of cell. On the other hand, the power stability of the pump laser is controlled to be less than 0.05%. Compared with traditional methods, the complicated calculation process in optical design is better solved, and a higher uniformity with slight energy loss is achieved.
为了提高用于无自旋交换弛豫惯性测量装置的泵浦激光器的精度和光束质量，我们采用了一种方案来实现泵浦激光器的方波调制和功率稳定性控制，并采用另一种方案来获得激光束的均匀强度分布，其中使用声光调制器（AOM）和比例积分微分（PID）控制器来实现前者，基于TracePro软件设计并优化了自由曲面透镜以实现后者。在实验中，通过AOM的一阶衍射光束光斑尺寸约为1.1×0.7mm，在自由曲面透镜后方放置了半径为7mm的球形气室。结果表明，在模拟和实验中，在半径为7mm的目标区域内，重塑强度分布的均匀性均高于90%，这确保了均匀激光束覆盖气室区域。另一方面，泵浦激光器的功率稳定性控制在小于0.05%。与传统方法相比，更好地解决了光学设计中复杂的计算过程，并且在能量损失较小的情况下实现了更高的均匀性。
