Chinese Physics Letters
Temperature Dependence of Dark Lines in Coherent Population Trapping
Jianliao Deng, Zhengfeng Hu, He Huijuan, Yuzhu Wang
Abstract
We measure the signal amplitude and linewidth of a dark line in coherent population trapping in the Rb vapour cell filled with mixed buffer gas N 2 and Ar as a function of cell temperature. We find that the dark line signal amplitude increases with temperature up to a maximum at 49°C and then drops at higher temperatures due to quenching effects of N 2 . The linewidth of the dark line remains basically constant, at 1080 Hz. We also measure the linewidth of the dark line as a function of laser intensity. The linewidth increases linearly with laser intensity. An intrinsic linewidth (FWHM=896 Hz at 3.4 GHz) of the Rb cell is obtained.