Centilitre-scale vacuum chamber with integrated grating magneto-optical trap optics for compact ultracold quantum technologies

A key enabling component for cold atom technologies are compact ultra-high vacuum systems, which facilitate high precision quantum sensing applications.  Whilst there has been progress towards portable compact vacuum systems, their size, weight and power usage can be prohibitively large.  Here, we present a centilitre-scale ceramic vacuum chamber with He-impermeable viewports and an integrated diffractive optic, allowing simple and robust laser cooling from a single circularly-polarised laser beam.  A demonstration of a portable cold atom source based on this vacuum system delivers 10⁷ laser-cooled ⁸⁷Rb atoms per second.  Pressure measurement from magneto-optical trap loading curves gauges the pressure to be below 10^-7 mbar under active pumping.  The pressure under passive pumping stabilizes to 3 x 10^-6 mbar with a 17 day time constant - which has already been verified for a year without active pumping.  The passive pumping vacuum lifetime is estimated to be several years, from short-term He throughput measurements,  and there are many foreseeable improvements.  This technology is a key step towards realising wide-ranging mobilization of ultracold quantum sensing. [see also arxiv:2101.07851]