銣原子5S1/2 → 5D5/2 雙光子躍遷在原子分子光學領域為非常重要的躍遷，
且其頻率被國際度量衡委員會公開發表，量測此原子譜線的絕對頻率為本論文首
要目的，然而根據本實驗室石宇哲學長先前的量測，量測的譜線(總共九條) 皆與
國際標準值差距了30 kHz 左右，我們猜測主要有兩個原因，一為隔磁材料坡莫合
金(permalloy) 無法有效隔磁，進而產生賽曼偏移(Zeeman shift)，因此設計了荷
姆霍茲線圈製造無磁場環境；二為玻璃器室內部有未知氣體，進而碰撞產生氣壓
偏移(pressure shift)，因此架設了一套真空系統，製造只有純銣原子之氣室。
為了使掃描出來的原子譜線有良好的重複率以及穩定性，我們先使用Pound-
Drever Hall 鎖頻技術使雷射抖動範圍從3MHz 縮小至0.6 MHz；再來我們使用電
光調制法將原子鎖在交叉譜線上，使雷射頻率在鎖頻過程不會受到調制影響，且
頻率可由電光調制器控制，使我們進而掃頻。
在使用荷姆霍茲線圈的過程中，我們逐步增加反向磁場的大小並記錄譜線線
寬，當線寬為最小值時，代表譜線沒有因為受到磁場影響，此時所量得的絕對頻
率仍與國際標準值差距30kHz，因此我們認為這個差距並非磁場隔絕不好所造成
的。
在抽真空過程中，我們使用渦輪幫浦將真空腔氣壓抽至1 × 10−7 Torr，並利
用推拉式真空導引將內部銣原子安瓿打破，並利用溫度梯度讓原子大量沉澱在玻
璃旁，將其當成冷端凝子(cold finger)。此外，我們也利用780 nm 雷射探測銣原
子5S1/2 → 5P3/2 單光子躍遷，利用穿透光的凹陷程度計算原子密度比，進而推
算原子蒸氣壓。最終我們量測出雙光子躍遷之頻率，並與美國國家標準局(NIST)
提供的值非常接近。

In this thesis, we have measured the clock transition of rubidium. we first
developed the differential Zeeman shift by Helmholtz coil, which coefficient of 87Rb
5S(F = 2) → 5D(F = 4) is −48.9 ± 2.6 kHz/G. After that, we have measured
the Rb self-collision shift in a vacuum chamber system, and the linear coefficient is
−120±70 Hz/μTorr. On the other hand, For the stability of the frequency-stabilized
laser, the Allan deviation can reach 3×10( − 13) within 1000 second of integration
time. Finally, we have measured the rubidium 5S1/2(F = 3) → 5D5/2(F′ = 1 ∼ 5)
transition, and the results are only ±5 kHz difference with the suggested value of
Certificate in Investment Performance Measurement(CIPM).

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