我們分別在室溫及磁光陷阱中觀測銫原子在電磁引發透明時所產生doubly dressed state及sub-natural linewidth的現象，在梯階式的系統下觀測到銫原子吸收所造成能階的分裂與競爭以及小於D2 line自然線寬的躍遷3.5 MHz。
我們利用探測雷射將銫原子從基態|62S1/2 ,F＝4>激發至|62P3/2 ,F=5>，再用耦合雷射將電子從|62P3/2 ,F＝5>激發至|82S1/2 ,F=4>來形成一組階梯式的系統。當探測雷射與耦合雷射同時符合銫原子的躍遷頻率時我們可以觀測到量子干涉效應下的電磁引發透明現象。
實驗中我們改變探測雷射的光强度、調變及利用抑制與恢復的方法來觀測在電磁引發透明的現象下探測雷射穿透與吸收的情形。並期望在未來的實驗裡能夠在四能階的系統下觀測到更多量子干涉效應的現象。

We observed the phenomena of doubly dressed state and sub-natural linewidth under the electromagnetic induced transparency (EIT) processes of Cs atom at room temperature or cold sample. In the cascade type system, the Cs atom was probed from |62S1/2 ,F＝4> state to |62P3/2 ,F=5> state, and coupled from |62P3/2 ,F＝5> state to |82S1/2 ,F=4> state. The EIT phenomenon due to quantum interference can be observed while the probe and coupling laser are both on resonance. In our experiments, the transmission of probe laser was monitored while changing the Rabi frequency or detuning of probe laser. The effects of quantum interference such as EIT, EIA and Mollow spectrum were observed, and can be understood by solving a steady state density matrix. Using “suppression and recovery” method in the magneto-optical trap, a sub-natural linewidth figure was demonstrated in the cascade system of cold Cs atom. In the future work, we would like to study more aspects of quantum effect phenomena on four level systems.

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