用短程飞行时间吸收谱对铯磁光阱中冷原子温度的测量  

Temperature measurement of cold atoms in a cesium magneto-optical trap by means of short-distance time-of-flight absorption spectrum

作　　者：耿涛[1] 闫树斌[1] 王彦华[1] 杨海菁[1] 张天才[1] 王军民[1] 

机构地区：[1]量子光学与光量子器件国家重点实验室,山西大学光电研究所,太原030006

出　　处：《物理学报》2005年第11期5104-5108,共5页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:60178006;10434080;10374062);教育部科学技术重点项目(批准号:204019);山西省青年学术带头人科研项目经费资助的课题.~~

摘　　要：介绍采用短程飞行时间吸收谱测量铯原子磁光阱(MOT)中冷原子温度的基本原理及实验实现.与通常的飞行时间方法不同,采用短程飞行时间吸收谱来测量MOT中冷原子云的温度.在MOT区域正下方若干毫米处入射一束圆柱状共振探测光束(实验中对于h=3mm,5mm,8mm的情况均作了研究),释放冷原子云,在其膨胀和自由下落过程中穿过探测光束,即可由光电探测器测得飞行时间吸收谱,由此推得MOT中冷原子的温度.We report the basic idea and experimental demonstration of measuring the temperature of cold cesium atomic cloud confined in a magneto-optical trap （MOT） by analyzing absorption spectrum observed in the short-distance time-of-flight （TOF） method. Compared with the conventional TOF scheme, we measure the temperature of cold atomic cloud in MOT by short-distance TOF method for our small vapor cell. If the cold atomic cloud is released, it will fall and expand due to gravity and its initial velocity distribution. Utilizing a cylindrical resonant probe beam positioned several millimeters beneath the MOT （in this paper, we analyzed the cases for 3mm, 5mm, and 8mm of center-to-center distance between the MOT region and the probe beam, respectively）, we can record the short-distance TOF absorption spectrum with a photodiode when cold atoms go through the probe region. Analysis of the short-distance TOF absorption spectrum yields the effective temperature of the cold cloud in MOT.

关 键 词：磁光阱 冷原子 飞行时间 短程飞行时间 铯原子 飞行时间 冷原子云 吸收谱 磁光阱 铯原子 温度 测量 短程 光电探测器 

分 类 号：O562.2[理学—原子与分子物理]