We demonstrate a novel way to form and deplete a vapor-cell magneto-optic trap (MOT) using a reversible, solid-state alkali-metal source (AMS) via an applied polarized voltage. Using ~100 mW of electrical power, a trapped-atom number of 5×10 6 has been achieved starting from near zero and the timescales of the MOT formation and depletion of ~1 s. This fast, reversible, and lowpower alkali-atom source is desirable in both tabletop and portable cold-atom systems. The core technology of this device should translate readily to other alkali and alkaline-earth elements that could find a wide range of uses in cold-atom systems and instruments.
I. BackgroundLaser cooling has revolutionized atom-based sensors and instrumentation. The low temperature of the atoms allows for long interaction periods and narrow spectroscopic linewidths that are critical for precision measurements. In all cold-atom systems, a source of (warm) atoms is required to provide an appropriate atom density for forming the MOT. Commercial rubidium (Rb) and cesium (Cs) alkali-metal dispensers (AMDs) 1 have been widely used in laboratory-based cold-atom experiments for decades due to their reliability and long lifetimes. However, these AMDs release alkali atoms via resistive heating, often requiring several watts during operation. Furthermore, dispensing via resistive heating is a non-reversible process; once the alkali metal is created, it cannot be recovered by the dispenser. This type of dispensing not only hinders the ability to precisely control the alkali-atom density for a cold-atom system over a large environmental temperature range, but also results in a long time constant for the alkali-atom density to decay, which negatively impacts the cycling rate, and hence performance, of cold-atom metrological experiments 2,3,4 . Such effects limit the use of AMDs in field-deployable, long-lifetime compact cold-atom sensors and clocks 5,6 .On the other hand, techniques like laser-ablated or current-pulsed AMDs 7,8,9 and light-induced atomic desorption (LIAD) 10,11,12,13 have been developed to considerably enhance the possibilities of modulating alkali-atom density in cold-atom systems. However, none of these techniques simultaneously meet the requirements of being fast, reversible, low-power and able to be miniaturized, which are important for developing a portable cold-atom physics package.Recent efforts have focused on novel solid-state alkali sources that operate via an electrolysis process 14,15 . A promising candidate material for this process is a beta double-prime alumina ( "alumina) ceramic, which features a high ionic mobility for alkali ions. By utilizing an applied voltage to control the flux of mobile alkali ions within the ceramic, this device has previously demonstrated bidirectional vapor-phase Rb sourcing and sinking functionality 16,17,18 . In this letter, we describe the novel implementation of a voltage-controlled, solid-state " -alumina Rb AMS to demonstrate the formation and depletion of a Rb MOT in a vapor cell.