放電管產生的鈣離子之吸收光譜

本論文描述利用鈣離子的吸收光譜，來測試放電腔體是否有產生鈣離子的方法。放電腔體由內建兩個金屬平板的真空系統所組成。氣壓可以達到 6.8×〖10〗^(-7) Torr。金屬平板經由通高壓直流電源或交流電源產生電漿以及鈣離子。我們以397奈米雷射將鈣離子從低能階4S1/2激發到高能階4P1/2。397奈米雷射是由795奈米雷射經過內含倍頻晶體的共振腔而得。795奈米雷射由功率為25毫瓦的二極體雷射出光，經過雷射功率放大器後為180毫瓦。本實驗用了兩種雷射穩頻方法:Hansch-Couillaud method 和 Pound-Drever-Hall technique。倍頻後的397奈米雷射功率大約為40微瓦。未來我們計畫用中空陰極管來實現鈣離子飽和吸收光譜，再用鎖頻後的397奈米藍光來雷射冷卻由離子井捕捉的鈣離子。

關鍵字

雷射穩頻；吸收光譜；二極體外腔雷射；直流放電；交流放電

並列摘要

This thesis describes the method of absorption spectroscopy of calcium ions to test our discharge chamber. The discharge chamber has been set up. It contains two conduction plates and a vacuum system in which the vacuum can reach 6.8×〖10〗^(-7) Torr. High-voltage DC and RF power source have been applied to the conduction plates. We attempt to use the 397 nm laser light to excite 40Ca+ ions from the ground state 4S1/2 to the excited state 4P1/2. The 397 nm light is produced by frequency doubling of the 795 nm laser. We use an enhancement cavity with a LBO crystal to increase the efficiency of frequency doubling. The 795 nm external cavity diode laser of power about 25 mW is sent into a tapered amplifier and the final output power of the 795 nm light is about 180 mW. As for the locking system, we demonstrate two laser frequency stabilization systems including the Hansch-Couillaud method and the Pound-Drever-Hall technique. The power of the blue light produced by SHG is about 40 micro watt. In the future, we plan to carry out the saturation absorption spectroscopy of calcium ions in a hollow cathode lamp. The frequency-stabilized laser at 397 nm will be used for laser cooling of trapped calcium ions.

並列關鍵字

laser frequency stbilization ； absorption spectroscopy ； external cavity diode laser ； DC discharge ； RF discharge

參考文獻

[1] H.L. Shu, H. Guan, X.R. Huang, J.M. Li and K.L. Gao. “A Single Laser Cooled Trapped 40Ca+ Ion in a Miniature Paul Trap” Chin. Phys. Lett. 22 (2005), 1641

[2] H. Guan, B. Guo, G.L. Huang, H.L. Shu, X.R. Huang and K.L. Gao. “Stabilization of the 397 nm and 866 nm external cavity diode lasers for cooling a single calcium ion” Opt. Commun. 274 (2007), 182

[3] H. Guan, Q. Liu, Y. Huang, B. Guo, W.C. Qu, J.A. Cao, G.L. Huang, X.R. Huang, K.L. Gao. “A 729 nm laser with ultra-narrow linewidth for probing 4S1/2–3D5/2 clock transition of 40Ca+” Opt. Commun., 284 (2011), 217

[4] Q. Liu, Y. Huang, J. Cao, B.Q. Ou, B. Guo, H. Guan, X.R. Huang and K.L. Gao. “Frequency Measurement of the Electric Quadrupole Transition in a Single Laser-Cooled 40Ca+” Chin. Phys. Lett., 28 (2011), 013201

[5] B. Barbieri, N. Beverini, A. Sasso. “Optogalvanic spectroscopy” Rev. Mod. Phys. 62 (1990), 603

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放電管產生的鈣離子之吸收光譜

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