Morrissey Michael J, Deasy Kieran, Wu Yuqiang, Chakrabarti Shrabana, Nic Chormaic Síle
Department of Applied Physics and Instrumentation, Cork Institute of Technology, Cork, Ireland.
Rev Sci Instrum. 2009 May;80(5):053102. doi: 10.1063/1.3117201.
We present a novel technique for measuring the characteristics of a magneto-optical trap (MOT) for cold atoms by monitoring the spontaneous emission from trapped atoms coupled into the guided mode of a tapered optical nanofiber. We show that the nanofiber is highly sensitive to very small numbers of atoms close to its surface. The size and shape of the MOT, determined by translating the cold atom cloud across the tapered fiber, is in excellent agreement with measurements obtained using the conventional method of fluorescence imaging using a charge coupled device camera. The coupling of atomic fluorescence into the tapered fiber also allows us to monitor the loading and lifetime of the trap. The results are compared to those achieved by focusing the MOT fluorescence onto a photodiode and it was seen that the tapered fiber gives slightly longer loading and lifetime measurements due to the sensitivity of the fiber, even when very few atoms are present.
我们提出了一种新颖的技术，通过监测捕获原子的自发辐射耦合到锥形光学纳米纤维的导模中，来测量冷原子磁光阱（MOT）的特性。我们表明，纳米纤维对靠近其表面的极少数原子高度敏感。通过将冷原子云平移穿过锥形纤维来确定的MOT的尺寸和形状，与使用电荷耦合器件相机的传统荧光成像方法获得的测量结果非常吻合。原子荧光耦合到锥形纤维中还使我们能够监测阱的加载和寿命。将结果与通过将MOT荧光聚焦到光电二极管上所获得的结果进行比较，发现由于纤维的敏感性，即使存在非常少的原子，锥形纤维给出的加载和寿命测量值也略长。
