Magneto-optical trapping forces for atoms and molecules with complex level structures
Magneto-optical trapping forces for atoms and molecules with complex level structures
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DOI：
10.1088/1367-2630/17/1/015007
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发表时间：
2014-08
影响因子：
3.3
通讯作者：
M. Tarbutt
中科院分区：
文献类型：
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作者：
M. Tarbutt
分子的激光冷却和磁光捕获通常涉及由几个激光频率驱动的多个跃迁。我们分析了如何磁光捕获力依赖于角动量，Fl和Fu，和g-因子，gl和gu，较低和较高的状态。当F l > F u？>相对于Fu ≥ Fl的情况，偏振必须反转。?>圆偏振的正确选择取决于gu的符号而不取决于gl的符号。如果gu为零，则没有捕获力，并且当gu与gl相比小时，捕获力非常弱，当冷却转变为2？> 2 1 / 2？一个分子的转变。对于某些分子，混合的激发2 1 / 2？> #21518;，与附近的2？激发态可以大大增加Gu，导致更强的捕获力。磁场和激光偏振的快速同步反转也能产生强的俘获力。我们模拟了最近的磁光捕获SrF分子的实验，并建议，另一种选择的激光束偏振将加强捕获力。
Laser cooling and magneto-optical trapping of molecules typically involves multiple transitions driven by several laser frequencies. We analyze how magneto-optical trapping forces depend on the angular momenta, Fl and Fu, and the g-factors, gl and gu, of the lower and upper states. When F l > F u ?> the polarizations must be reversed relative to cases where F u ≥ F l . ?> The correct choice of circular polarization depends on the sign of gu but not on the sign of gl. If gu is zero there is no trapping force, and the trapping force is very weak whenever gu is small compared to gl, which it usually is when the cooling transition is the 2 &Sgr; ?> to 2 &Pgr; 1 / 2 ?> transition of a molecule. For some molecules, mixing of the excited 2 &Pgr; 1 / 2 ?> state with a nearby 2 &Sgr; ?> excited state can greatly increase gu, leading to stronger trapping forces. A strong trapping force can also be produced by rapidly and synchronously reversing both the magnetic field and the laser polarizations. We simulate a recent experiment on magneto-optical trapping of SrF molecules, and suggest that an alternative choice of laser beam polarizations will strengthen the trapping force.