為研究電磁誘發透明現象，我們利用外腔二極體雷射(ECDL)作為探測雷射，其頻率鎖在Cs D2 |6S1/2,F=4>→|6P3/2,F′=5>躍遷頻率，並引入一反向Ti:sapphire laser作為耦合雷射，以Cs超精細能階分裂躍遷|6P3/2,F′=5>→|8S1/2,F′′=4>為頻率中心頻率掃動100MHz，並觀測探測雷射在銫原子中的電磁誘發透明光譜。影響電磁誘發透明譜線線寬有諸多因素，例如:探測雷射和耦合雷射的Rabi frequency、碰撞增寬、介質之光學密度…等等，在此固定探測雷射和耦合雷射的Rabi frequency改變溫度來觀測電磁誘發明譜線線寬之變化，發現隨溫度增高電磁誘發明譜線線寬會隨之減少，我們考慮各上述種因素並將實驗數據和理論模型進行擬合發現cascade-type 的電磁誘發透明譜線線寬受到最高激發態之dephasing rate影響最大，並發現高激發態之dephasing rate隨溫度上升而增加。

The thermal effect on the linewidth of electromagnetically induced transparency (EIT) is studied in cesium vapor cell. The temperature dependence on the linewidth of a cascade-type EIT was observed by using a frequency locked external cavity diode laser (ECDL) as probe beam and a Ti:sapphire laser as coupling beam to scan cross the resonance of the excited state Cs |6P3/2,F′=5>→|8S1/2,F′′=4>. The temperature of cesium vapor cell was varied and stabilized to investigate the thermal effect on the EIT linewidth. Using a theoretical model to solve the optical Bloch equation (OBE), a simulated spectrum is agree well with the experimental data. The relation between the dephasing rate and cell temperature was found that the dephasing rate increase as cell temperature rised, for 15⁰C, 25⁰C, 35⁰C the average dephasing rates are 3.3 MHz, 3.8 MHz, 4.5 MHz respectively. The center position of the EIT peak relative to the peak from the reference cell at fixed temperature of 25⁰C is measured and found shift with a rate of 3.1 kHz/⁰C.

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