磁四极阱中参量共振诱导的原子冷却

通过周期性地调制势阱，从实验上证明了四极阱的非简谐特性可以被用来冷却被囚禁的原子。该冷却效应是由势阱中热原子的能量选择性逃逸和剩余原子的热平衡所致。研究了调制后的势阱中剩余原子的温度以及原子数对调制频率的依赖关系。另外还证明了参量共振诱导的原子冷却技术也能提高原子的相空间密度。

It is demonstrated experimentally that the anharmonic property of the quadrupole trap can be exploited to cool trapped atoms by modulating the trap potential anisotropically. This cooling effect arises from the energy-selective removal of the most energetic trapped atoms and the thermal equilibrium of the remaining atoms. The frequency dependences of the temperature and the fraction of the atoms left in the trap after the modulation are explored. It is also demonstrated that the cooling induced by parametric resonance can also increase the phase space density of the trapped atoms.