A compact, high-flux source of cold atoms

The ongoing drive to transfer quantum technologies from research laboratories to practical, portable devices requires the development of multiple key enabling technologies. The field of cold atoms, which includes high-precision metrology and quantum simulation, has various real-world applications including time-keeping and navigation. A crucial component in these systems is a cold-atom source that generates a flux of low-velocity atoms suitable for subsequent capture. A large flux enables fast repetition rates, high duty cycles, long measurement times, and resistance to long-term performance degradation with a good signal-to-noise ratio, all of which are essential to produce cold-atom devices and technologies that are capable of out-performing the classical alternatives. This thesis presents the design, fabrication and characterisation of a novel cold-atom source using a compact pyramidal magneto-optical trap (MOT) with a unique adjustable-aperture mechanism. This allowed an investigation of the dependence of the flux characteristics on the aperture size, a parameter space that has not previously been explored. The measurements showed a strong dependence of the flux on the aperture size, with a negligible flux below 0.4mm, then an approximately linear increase up to 1.0mm, at which point the relationship showed possible signs of saturation. Using 87Rb, a flux of 1.18×1010 atoms/s was produced using a 1.27mm aperture, for which the mean velocity of the atoms was 21.6(3) m/s with a FWHM of 11.2(2) m/s, and the FWHM divergence of the beam was 86(2) mrad. This is the highest recorded flux from a pyramid or 2D+-MOT source, and amongst the highest reported fluxes from any MOT sources, and avenues for improvement still remain. This work fulfils the aim of demonstrating a compact and robust cold-atom source generating a high flux of laser-cooled atoms for real-world quantum technology applications.