Extending the trapping lifetime of single atom in a microscopic far-off-resonance optical dipole trap  

作　　者：Jun HE Bao-dong YANG Yong-jie CHENG Tian-cai ZHANG Jun-min WANG 

机构地区：[1]State Key Laboratory of Quantum Optics and Quantum Optics Devices, and Institute of Opto Electronics, Shanxi University, Taiyuan 030006, China

出　　处：《Frontiers of physics》2011年第3期262-270,共9页物理学前沿（英文版）

基　　金：Acknowledgements This work was supported by the Na- tional Natural Science Foundation of China （Grant Nos. 60978017, 61078051, and 10974125）, the project from excellent research team from the National Natural Science Foundation of China （Grant No. 60821004）, and the NCET Program from the Ministry of Educa- tion of China （Grant No. NCET-07-0524）.

摘　　要：In our experiment, a single cesium atom prepared in a large-magnetic-gradient magneto optical trap （MOT） can be efficiently transferred into a 1064-nm far-off-resonance microscopic optical dipole trap （FORT）. The efficient transfer of the single atom between the two traps is used to determine the trapping lifetime and the effective temperature of the single atom in FORT. The typical trapping lifetime has been improved from ~ 6.9 s to ~ 130 s by decreasing the background pressure from 1 × 10^-10 Torr to ~ 2 × 10^-11 Torr and applying one-shot 10-ms laser cooling phase. We also theoretically investigate the dependence of trapping lifetimes of a single atom in a FORT on trap parameters based on the FORT beam＇s intensity noise induced heating. Numerical simulations show that the heating depends on the FORT beam＇s waist size and the trap depth. The trapping time can be predicted based on effective temperature measurement of a single atom in the FORT and the intensity noise spectra of the FORT beam. These experimental results are found to be in agreement with the predictions of the heating model.In our experiment, a single cesium atom prepared in a large-magnetic-gradient magneto optical trap （MOT） can be efficiently transferred into a 1064-nm far-off-resonance microscopic optical dipole trap （FORT）. The efficient transfer of the single atom between the two traps is used to determine the trapping lifetime and the effective temperature of the single atom in FORT. The typical trapping lifetime has been improved from ~ 6.9 s to ~ 130 s by decreasing the background pressure from 1 × 10^-10 Torr to ~ 2 × 10^-11 Torr and applying one-shot 10-ms laser cooling phase. We also theoretically investigate the dependence of trapping lifetimes of a single atom in a FORT on trap parameters based on the FORT beam＇s intensity noise induced heating. Numerical simulations show that the heating depends on the FORT beam＇s waist size and the trap depth. The trapping time can be predicted based on effective temperature measurement of a single atom in the FORT and the intensity noise spectra of the FORT beam. These experimental results are found to be in agreement with the predictions of the heating model.

关 键 词：magneto optical trap （MOT） far-off-resonance optical dipole trap （FORT） singleatom trapping lifetime release-and-recapture method （R＆R） effective temperature 

分 类 号：TN248[电子电信—物理电子学] U483[交通运输工程—载运工具运用工程]