對於原子物理的研究而言，鉈原子是其中相當重要的一個元素。在近年來許多關於宇稱不守恆與電子電偶極的研究中都利用鉈原子進行理論計算與實驗量測。如果能夠對於鉈原子的超精細光譜與原子結構能有更進一步的瞭解，將有助於提供理論計算的實驗依據。

本實驗量測鉈原子 6P3/2 → 6D5/2 , 3/2能階躍遷的螢光光譜、205Tl 6P3/2 , F=2 → 6D5/2 , F=3的絕對頻率與研究鉈原子利用6P3/2 → 6D5/2能階躍遷雷射冷卻之可能性。螢光光譜的量測是利用鈦藍寶石雷射所輸出的755nm與704nm的紅光經倍頻共振腔得到實驗需要的377 nm與352 nm的紫光，量得205Tl 6D5/2 能階的超精細能階分裂（hyperfine splitting）為686 (16) MHz，其中F=2 → F=3 的線寬（FWHM）為46 MHz；203Tl 6D5/2 能階的超精細能階分裂為698 (21) MHz，其中F=2 → F=3 的線寬（FWHM）為60 MHz。絕對頻率的量測利用飛秒光頻梳首次量測到205Tl在6P3/2 , F=2 → 6D5/2 , F=3的能階躍遷絕對頻率值為851634646（56）MHz，這是第一次此能階躍遷絕對頻率被量測到。鉈原子雷射冷卻依照目前實驗室的光源狀況而言，效果可以把鉈原子從12.7 m/s 減速至
12.1 m/s。

未來的工作在光譜部分除了量測出鉈原子在6P3/2 → 6D3/2的能階躍遷光譜外，也將利用飛秒光頻梳量測6P3/2 → 6D3/2的超精細能階躍遷。此外如果要進一步研究鉈原子雷射冷卻，則可空間掃瞄偵測鉈原子的粒子偵測器將是需要製作的儀器。

The spectroscopy of atomic thallium 6P3/2 → 6D5/2 transition has been observed by laser-induced fluorescence (LIF). The absolute frequency of atomic thallium (205Tl) 6P3/2 , F=2 → 6D5/2 , F=3 transition has been measured for the first time to an uncertainty of 56 MHz using the femtosecond optical frequency comb and the measured absolute frequency of this transition is
851634646 (56) MHz .The possibility of laser cooling of atomic thallium has also been studied and the calculation shows that the velocity of atomic thallium could be deceased to 12.1 m/s .

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