Investigation of low-outgassing lithium sources for a portable cold-atom vacuum standard

The aim of the Cold Core Technology Platform at NIST is to produce chip-scale sensors and standards based on cold atoms, including a device based on trapped cold atoms which is simultaneously a primary standard and an absolute sensor of vacuum. Translating these cold atom-based technologies into deployable sensors requires an atomic source which is scaleable, lightweight, and suitable for ultra-high vacuum. We present two potential atom sources for such applications. One, an alkali metal dispenser made from 3D-printed titanium, loads a Li magneto-optical trap (MOT) of 10\textasciicircum 7 atoms with a low outgassing rate. In a second application, atoms are loaded into a MOT by light-induced atomic desorption (LIAD) from the surface of a vacuum viewport. A MOT of roughly 10\textasciicircum 4 atoms was loaded in this manner while increasing the pressure in the vacuum chamber by less than 50{\%}, or 2x10\textasciicircum -10 torr. To our knowledge, this is the first observation of LIAD of Li.