Extraction dynamics of electrons from magneto-optically trapped atoms
Extraction dynamics of electrons from magneto-optically trapped atoms
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DOI：
10.1063/1.4991366
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发表时间：
2017-07
影响因子：
4
通讯作者：
O. Fedchenko;S. Chernov;A. J. McCulloch;M. Vielle-Grosjean;D. Comparat;G. Schönhense
中科院分区：
文献类型：
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作者：
O. Fedchenko;S. Chernov;A. J. McCulloch;M. Vielle-Grosjean;D. Comparat;G. Schönhense
磁光阱中激光冷却原子的脉冲光电离有可能产生几meV带宽和几ps脉冲长度的冷电子束。这样的光源对于研究快速低能过程如相干声子激发将是非常有吸引力的。为了研究基于MOT的源同时产生冷电子和快电子的适用性，我们研究了囚禁Cs原子的光电离动力学。一个动量显微镜般的设置与延迟线检测器允许同时测量的空间和时间的电子分布。测量的图案是复杂的，由于洛伦兹力诱导螺旋轨迹。光线跟踪模拟再现了主要特征。我们发现，生产电子束的带宽为几毫电子伏是简单的，但是，在ps范围内的脉冲更苛刻，需要束消隐或部分阻断。
Pulsed photoionization of laser-cooled atoms in a magneto-optical trap (MOT) has the potential to create cold electron beams of few meV bandwidths and few ps pulse lengths. Such a source would be highly attractive for the study of fast low-energy processes like coherent phonon excitation. To study the suitability of MOT-based sources for the production of simultaneously cold and fast electrons, we study the photoionization dynamics of trapped Cs atoms. A momentum-microscope-like setup with a delay-line detector allows for the simultaneous measurement of spatial and temporal electron distributions. The measured patterns are complex, due to the Lorentz force inducing spiral trajectories. Ray-tracing simulations reproduce the main features. We find that the production of electron bunches with bandwidths of a few meV is straightforward; however, pulses in the ps-range are more demanding and require beam blanking or partial blocking.