Wang Junmin, Wang Jing, Yan Shubin, Geng Tao, Zhang Tiancai
State Key Laboratory of Quantum Optics and Quantum Optics Devices and Institute of Opto-Electronics, Shanxi University, 92 Wucheng Road, Taiyuan 030006, Shanxi, People's Republic of China.
Rev Sci Instrum. 2008 Dec;79(12):123116. doi: 10.1063/1.3058607.
A novel scheme of transferring cold atoms in a double magneto-optical trap (MOT) system has been experimentally demonstrated. Cold cesium atoms trapped in a vapor-cell MOT are efficiently transferred to an ultrahigh-vacuum (UHV) MOT by a continuous-wave divergent Gaussian transfer laser beam. When large red detuning and moderate intensity are adopted for the transfer laser beam, enhancement of the recapturing of atoms in the UHV MOT is clearly observed. Using the divergent transfer laser beam (diameter of approximately 1.60 mm in the vapor-cell MOT region) with typical power of approximately 20.2 mW, up to approximately 85% of transfer efficiency is obtained when the frequency detuning is set to around -1.2 GHz, and it is not sensitive to small detuning variation. This transfer is much efficient compared with that in the case of continuous-wave near-resonance weak transfer laser beam (typical power of order of approximately 100 microW and typical frequency detuning of approximately-10 MHz) which is normally used in double-MOT experiment. The enhancement is ascribed to the guiding effect on cold atomic flux by transverse dipole potential of the large red-detuned transfer laser beam.
一种在双磁光阱（MOT）系统中转移冷原子的新方案已通过实验得到证实。捕获在气室MOT中的冷铯原子通过连续波发散高斯转移激光束被有效地转移到超高真空（UHV）MOT中。当转移激光束采用大的红失谐和适中的强度时，可以清楚地观察到UHV MOT中原子重新捕获的增强。使用发散转移激光束（在气室MOT区域直径约为1.60毫米），典型功率约为20.2毫瓦，当频率失谐设置在-1.2吉赫兹左右时，可获得高达约85%的转移效率，并且对小的失谐变化不敏感。与双MOT实验中通常使用的连续波近共振弱转移激光束（典型功率约为100微瓦量级，典型频率失谐约为-10兆赫兹）相比，这种转移效率更高。这种增强归因于大的红失谐转移激光束的横向偶极势对冷原子通量的引导作用。
