High-contrast coherent population trapping resonances using four-wave mixing in ~(87)Rb

摘要

We demonstrate very high-contrast coherent population trapping (CPT) resonances by using four-wave mixing in ~(87)Rb atoms. In the experiment, we take advantage of the spectral overlap between F(velence)2 -> F' and F(velence)3 -> F' optical resonances on the D1 line of ~(87)Rb and ~(85)Rb atoms, respectively, to eliminate the DC-light background from the CPT resonance signal. We observe a CPT resonance with a contrast in the range of 90percent, compared with a few percent achieved by alternative methods.