Barker D S, Norrgard E B, Scherschligt J, Fedchak J A, Eckel S
Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Phys Rev A (Coll Park). 2018 Oct;98(4). doi: 10.1103/PhysRevA.98.043412. Epub 2018 Oct 8.
We demonstrate loading of a Li magneto-optical trap using light-induced atomic desorption. The magnetooptical trap confines up to approximately 4 × 10 Li atoms with loading rates up to approximately 4 × 10 atoms per second. We study the Li desorption rate as a function of the desorption wavelength and power. The extracted wavelength threshold for desorption of Li from fused silica is approximately 470 nm. In addition to desorption of lithium, we observe light-induced desorption of background gas molecules. The vacuum pressure increase due to the desorbed background molecules is ≲ 50 % and the vacuum pressure decreases back to its base value with characteristic timescales on the order of seconds when we extinguish the desorption light. By examining both the loading and decay curves of the magneto-optical trap, we are able to disentangle the trap decay rates due to background gases and desorbed lithium. Our results show that light-induced atomic desorption can be a viable Li vapor source for compact devices and sensors.
我们展示了利用光致原子解吸对锂磁光阱进行加载。该磁光阱可俘获多达约4×10⁶个锂原子,加载速率高达约4×10⁶个原子每秒。我们研究了锂的解吸速率与解吸波长及功率的函数关系。从熔融石英中解吸出锂的提取波长阈值约为470纳米。除了锂的解吸,我们还观察到背景气体分子的光致解吸。解吸的背景分子导致的真空压力增加≲50%,当我们熄灭解吸光时,真空压力会在几秒量级的特征时间尺度内恢复到其基值。通过研究磁光阱的加载曲线和衰减曲线,我们能够区分由于背景气体和解吸的锂导致的阱衰减率。我们的结果表明,光致原子解吸对于紧凑型设备和传感器而言可以是一种可行的锂蒸汽源。