Highly sensitive detection of Rydberg atoms with fluorescence loss spectrum in cold atoms

Fluorescence loss spectrum for detecting cold Rydberg atoms with high sensitivity has been obtained based on lock-in detection of fluorescence of 6 P3/2 state when cooling lasers of the magneto-optical trap are modulated.The experiment results show that the signal to noise ratio has been improved by 32.64 dB when the modulation depth(converted to laser frequency)and frequency are optimized to 4 MHz and 6 kHz,respectively.This technique enables us to perform a highly sensitive non-destructive detection of Rydberg atoms.

基于Rydberg原子EIT光谱的激光频率锁定

本文利用Rydberg阶梯型三能级系统的电磁诱导透明光谱实现了509nm倍频激光器的无调制频率锁定。我们在实验中使用852nm激光和509nm激光在铯原子蒸汽池中构成阶梯型三能级体系,852nm激光器的频率锁定在铯原子6S1/2→6P3/2共振跃迁线上,509nm激光在铯原子激发态6P3/2→62D5/2Rydberg态的跃迁频率附近扫描获得了Rydberg态的电磁诱导透明光谱。利用852nm半导体激光器的频率调制作为参考信号,对探测的电磁诱导透明光谱信号进行解调得到误差信号,实现了509nm激光器的频率锁定。通过分析误差信号的频谱,对伺服电路的低频和高频反馈参数进行优化,获得的最佳锁定线宽约为533kHz,最小阿伦方差达到1.5×10^-11。