Fitch N J, Tarbutt M R
Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ, UK.
Chemphyschem. 2016 Nov 18;17(22):3609-3623. doi: 10.1002/cphc.201600656. Epub 2016 Sep 15.
We explore a technique for decelerating molecules using a static magnetic field and optical pumping. Molecules travel through a spatially varying magnetic field and are repeatedly pumped into a weak-field seeking state as they move towards each strong field region, and into a strong-field seeking state as they move towards weak field. The method is time-independent and so is suitable for decelerating both pulsed and continuous molecular beams. By using guiding magnets at each weak field region, the beam can be simultaneously guided and decelerated. By tapering the magnetic field strength in the strong field regions, and exploiting the Doppler shift, the velocity distribution can be compressed during deceleration. We develop the principles of this deceleration technique, provide a realistic design, use numerical simulations to evaluate its performance for a beam of CaF, and compare this performance to other deceleration methods.
我们探索了一种利用静磁场和光泵浦来使分子减速的技术。分子穿过空间变化的磁场，在朝着每个强场区域移动时被反复泵浦到弱场寻找态，而在朝着弱场移动时被泵浦到强场寻找态。该方法与时间无关，因此适用于使脉冲分子束和连续分子束减速。通过在每个弱场区域使用导向磁体，分子束可以同时被导向和减速。通过在强场区域逐渐减小磁场强度，并利用多普勒频移，可以在减速过程中压缩速度分布。我们阐述了这种减速技术的原理，给出了一个实际的设计方案，使用数值模拟来评估其对CaF分子束的性能，并将该性能与其他减速方法进行比较。
