Characteristics of a magneto-optical trap of molecules
Characteristics of a magneto-optical trap of molecules
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DOI：
10.1088/1367-2630/aa8e52
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发表时间：
2017-06
影响因子：
3.3
通讯作者：
H J Williams;S. Truppe;M. Hambach;L. Caldwell;N. Fitch;E. Hinds;B. Sauer;M. Tarbutt
中科院分区：
文献类型：
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作者：
H J Williams;S. Truppe;M. Hambach;L. Caldwell;N. Fitch;E. Hinds;B. Sauer;M. Tarbutt
研究了CaF分子的磁光阱（MOT）的性质。我们研究了从减速缓冲气冷光束加载MOT的过程，以及如何最好地减慢分子束以捕获最多的分子。我们确定了分子数、光子散射率、振荡频率、阻尼常数、温度、云大小和寿命对MOT关键参数的影响，特别是对主冷却激光器的强度和失谐的影响。我们将我们的结果与解析模型和数值模型、标准原子MOTs的性质以及SrF分子的MOTs进行了比较。我们加载了2 × 10 4个分子，并测量了每个分子的最大散射率为2.5 × 10 6 s−1，最大振荡频率为100 Hz，最大阻尼常数为500 s−1，最小MOT rms半径为1.5 mm。通过降低激光强度，获得了730 μK的最低温度。其寿命通常约为100ms，与分支比约为6 × 10−6的冷却循环泄漏一致。MOT的捕获速度约为11 m s−1。
We present the properties of a magneto-optical trap (MOT) of CaF molecules. We study the process of loading the MOT from a decelerated buffer-gas-cooled beam, and how best to slow this molecular beam in order to capture the most molecules. We determine how the number of molecules, the photon scattering rate, the oscillation frequency, damping constant, temperature, cloud size and lifetime depend on the key parameters of the MOT, especially the intensity and detuning of the main cooling laser. We compare our results to analytical and numerical models, to the properties of standard atomic MOTs, and to MOTs of SrF molecules. We load up to 2 × 10 4 molecules, and measure a maximum scattering rate of 2.5 × 10 6 s−1 per molecule, a maximum oscillation frequency of 100 Hz, a maximum damping constant of 500 s−1, and a minimum MOT rms radius of 1.5 mm. A minimum temperature of 730 μK is obtained by ramping down the laser intensity to low values. The lifetime, typically about 100 ms, is consistent with a leak out of the cooling cycle with a branching ratio of about 6 × 10 − 6 . The MOT has a capture velocity of about 11 m s−1.