我們使用實驗室的884奈米雷射系統，其包含了兩台外腔式半導體雷射，先將其中一台雷射之光頻率鎖在銫原子6S-6D交叉譜線訊號上，為主雷射。再利用偏頻鎖相的技術將主雷射與僕雷射的拍頻訊號以設定的參考頻率鎖在主雷射上，為僕雷射，此參考頻率由訊號產生器提供。藉由偏頻鎖相控制僕雷射頻率來掃描銫原子6S-6D的無都卜勒背景雙光子躍遷譜線。
接著，我們在銫原子氣室外圍給予一外加微弱磁場，並利用四分之一波片板，令銫原子吸收兩道圓偏振光。測量6S-6D的躍遷譜線之頻率中心隨磁場變化，並由數據擬合得出斜率，經由計算後，可以得知銫原子6D3/2的gJ值為0.77(4)。

I use an 884nm laser system which contains two parts. One is named “master laser system”, another one is named “slave laser system”. I lock the laser frequency of the master-laser system on the cross-over resonance of Cesium 6S to 6D hyperfine transition. For slave laser system, I offset lock the beat frequency between master and slave laser against a a function generator. So, I can change the frequency of slave laser by varying the aforementioned beat frequency, by which I am able to sweep the Cesium 6S to 6D Doppler-free two photons transition spectroscopy.
Next, we apply a weak magnetic field onto the atomic cesium, and use a quarter wave plate to make the cesium atom absorbing two circularly polarized lights. The variation of Cesium 6S-6D transition center frequency with the magnetic field is measured, and the slope is obtained by fitting the data. After calculation, the gJ value of the 6D 3/2 of the cesium atom is 0.77 (4).

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