紫外光诱导原子脱附技术在单腔磁阱装载中的应用

基于光诱导的原子脱附技术，采用脉冲紫外光剥离出玻璃池壁上吸附的铷原子以形成可快速开启和关断的脉冲铷原子源，成功地解决了单真空腔系统中磁阱的原子数和寿命之间的矛盾，突破了激光冷却和囚禁技术向小型化乃至微型化发展过程中的一个瓶颈.脉冲光源由390nm的LED阵列组成.实验结果表明它能够在1s内使真空铷原子气体分压提高近30倍,并且当紫外光关闭后系统的真空恢复到平衡状态的时间非常短，约120ms.测量了不同铷原子分压下磁光阱所俘获的最大原子数和装载时间,并由此得出系统的背景真空和磁光阱所能俘获的极限原子数，进一步得出磁阱的原子数-寿命积与磁光阱保持阶段时间的变化关系，结果显示在约1.25s处出现极大值，与无磁光阱保持阶段而直接进行磁阱装载情况相比提高了约0.3倍. 关键词：激光冷却磁光阱光诱导原子脱附原子数-寿命积

UV light-induced atom desorption for magnetic trap in single vacuum chamber

UV (390nm) light was used to modulate the rubidium partial pressure by inducing desorption of Rb atoms from the inner walls of the vacuum cell. A few mW/cm² of UV light was enough to increase the rubidium partial pressure by a factor of 30 in about 1 s. After the source was turned off, the pressure quickly decayed back to its previous value with a time constant as short as 120 ms, allowing for long tapping lifetimes after the MOT holding phase. The number-lifetime product of the magnetic trap was shown as a function of the duration of the MOT holding phase, the maximum value was achieved after a MOT holding time of 1.25 s.