三能级原子系统中单光子频率失谐对光减速的影响

Effect of one-photon detuning on light speed reduction in a three-level Λ-type atomic system

在Λ型三能级Rb原子介质中,观察到了由电磁感应透明(EIT)效应导致的光减速现象并测量了光延迟对单光子频率失谐量的依赖关系.结果表明,由于多普勒展宽效应的存在,在单光子频率失谐±600MHz的范围内,光减速效应较为显著.在考虑多谱勒频移的情况下,数值计算了光延迟随单光子频率失谐量的变化曲线,实验结果与理论曲线很好地符合.这一研究结果为利用单光子频率失谐控制光的群速度提供了理论与实验参考.

We have observed the reduction of group velocity of light via electromagnetically induced transparency （EIT） and measured the dependence of pulse delay on the one-photon detuning in a three-level ∧-type atomic system. The results show that due to the effect of Doppler broadening the light speed reduction is significant in a range of ± 600MHz one-photon detuning. Under the condition of considering the Doppler shift of frequency, the pulse delay as a function of the one-photon detuning is numerically calculated. The experimental measurements are in good agreement with the theoretical results. These researches provide theoretical and experimental references for controlling the group velocity of light by means of one-photon detuning.