Investigation of alkali vapor diffusion characteristics through microchannels

Abstract

We present Rb vapor transport through micro-scale capillaries on the impact of temperature and capillary inner diameters within the limits of the Knudsen number [Formula: see text]. Daily absorption spectral measurements were taken over several months to evaluate the dynamics of transport. We provide new insight into the diffusion mechanism and observe a quasi-single-layer coating on the surface based on the analysis of a slowly increasing absorption signal. The dwell time of the atom on the glass is directly derived from the diffusion dynamics at different temperatures. According to the mass flow rate, high vapor temperatures caused a faster transport speed, indicating rapid loading in microchannels. We provide a valuable model for future quantum device implementation through the use of miniaturized structures, such as photonic crystal fibers and optical waveguides.