本論文為了發展銣原子二級光鐘以建立時間頻率標準。實驗上，我們利用電光調制器將778 nm光纖雷射鎖在銣原子雙光子躍遷的交叉譜線。藉由改變電光調制器的調制頻率，進而改變雷射的頻率，以精密地量測銣原子5S-5D雙光子躍遷譜線。778 nm穩頻雷射的穩定度，在1秒的積分時間，Allan deviation已達到5×10^(-12)，因為量測受限於銫原子鐘的穩定度，所以我們認為778 nm穩頻雷射的穩定度會更好。
我們修正光強度偏移造成原子躍遷頻率偏移的影響，藉由超精細結構的能階間隔，推算A及B超精細結構常數為：
A(85Rb,5D5/2)：-2.2122(24) MHz，B(85Rb,5D5/2)：2.6881(38) MHz，A(87Rb,5D5/2)：-7.4595(29) MHz，B(87Rb,5D5/2)：1.2748(23) MHz。同位素偏移(Isotope shift)：160.630(7) MHz。

The aim of this thesis is to develop a rubidium secondary optical clock to establish a time and frequency standard. In this experiment, the 778 nm fiber laser is locked to crossover lines of rubidium two-photon transition via electro-optical modulator. When changing the modulation frequency of the electro-optic modulator, the laser frequency is correspondingly changed. So we can precisely measure the 5S-5D two-photon transition spectrum in rubidium.
For the stability of the 778 nm frequency-stabilized laser, the Allan deviation can reach 5×10^(-12) within 1 second of integration time. We believe that the stability of the 778 nm frequency-stabilized laser is better, because the measurement is limited by the stability of cesium atomic clock.
We correct the influence of the shift of atomic transition frequency caused by light intensity. In addition, we calculate the A and B hyperfine structure constants by using the energy level interval of hyperfine structure.
A(85Rb,5D5/2)：-2.2122(24) MHz, B(85Rb,5D5/2)：2.6881(38) MHz, A(87Rb,5D5/2)：-7.4595(29) MHz, B(87Rb,5D5/2)：1.2748(23) MHz. Isotope shift：160.630(7) MHz.

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