用于冷原子制备的激光扩束准直器的研制

Development of Laser Beam Expanding Collimator for Cold Atom Preparation

针对现有的冷原子实验用的多数保偏光纤输入型扩束准直器不能对输入激光束的偏振进行精确调节的缺陷,提出了一种全长度为135mm,输出圆形光斑有效直径为20mm的紧凑型偏振可调激光扩束准直器.该扩束准直器中的偏振棱镜和波片偏振轴均可独立调节,能对单模保偏光纤输入光束的偏振态进行精确调节和保持.所研制的激光扩束准直器在三维磁光阱冷原子实验中制备出了满足冷原子干涉实验要求的冷原子团,冷原子团原子数为5×108,温度约为10μK,并获得了最大上抛高度为1.156m的原子喷泉飞行时间信号.

Aiming at the defect that most polarization-maintaining fiber input beam expander collimators used in cold atom experiments can not accurately adjust the polarization of the input laser beam,a compact polarization-adjustable laser beam expanding collimator with a full length of 135 mm and an effective diameter of 20 mm for the output circular spot is proposed.The polarization axes of the polarization prism and the wave plate in the beam expander collimator can be independently adjusted,and the polarization state of the input beam of the single-mode polarization maintaining fiber can be accurately adjusted and maintained.The developed laser beam expanding collimator has prepared cold atomic groups that meet the requirements of cold atom interference experiment in the cold atom experiment of threedimensional magneto-optical trap.The atomic number of cold atomic groups was 5×108,the temperature was about 10μK,and the flight time signal of atomic fountain with the maximum throw-up height of1.156 m was obtained.