15min:

RAY-YUAN CHANG, Department of Physics, National Cheng-Kung University, Tainan 70101,Taiwan(R.O.C.); WEI-CHIA FANG, Department of Physics, National Cheng-Kung University, Tainan 70101, Taiwan(R.O.C.); MING-DA TSAI, Department of Physics, National Cheng-Kung University, Tainan 70101, Taiwan(R.O.C.); CHIN-CHUN TSAI, Department of Physics, National Cheng-Kung University, Tainan 70101, Taiwan(R.O.C.).

By using the technique of electromagnetically induced transparency(EIT), we have observed the quantum interference phenomenon in the lower-lying atomic Rydberg states of cold Cs atom in a magneto-optical trap (MOT) with typical atom numbers up to 1× 10⁷, and cloud temperature about 100µK. In our experiments, a grating feedback diode laser is frequency stabilized on the Cs atom via Doppler-free saturation absorption transition |6s~²S_1/2,~F=4> |6p~²P_3/2 ,~ F'=5>, and a tunable Ti:Sapphire laser scans across the |6p~²P_3/2,~ F'=5> |8s~²S_1/2, ~F''=4> transition frequency. Both spontaneous emission fluorescence from MOT and transmission intensity of the diode laser are monitored. A subnatural linewidth signal is obtained for probing the transition of Cs |6p~²P_3/2,~ F'=5> |8s~²S_1/2,~F''=4>. These signals correspond to the cascade EIT among the |6s~²S_1/2,~F=4> |6p~²P_3/2,~F'=5> | 8s~²S_1/2, ~F''=4 >.

This project is financially sponsored by National Science Council (grand no. NSC-95-2112-M-012-MY3).