Integrated photonics for atomic sensing

Abstract

Integrated photonics has become valuable to a wide range of applications including data communication, ranging, and inertial and chemical sensing. More recently, integrated photonics has also shown promise as a new means of trapping and probing atoms in atomic clocks. In this manuscript, we discuss how controlling the spatial properties of light emitted from an integrated photonics chip can support the realization of an atomic clock with drastically reduced size, weight, and power consumption. Specifically, atomic clocks require the intersection of three orthogonal beams, each with an area of approximately 16 mm2, to trap and probe a cloud of atoms. For good trapping, these beams need to be well collimated and polarized, and to exhibit intensity profiles that are as close to uniform as possible. For beams of these dimensions, this means new techniques need to be employed to control the rate at which light spreads across an integrated photonics chip, as well as the rate at which it diffracts out of the chip itself, all while maintaining good collimation. Existing integrated photonics technologies have been limited in the beam sizes they can generate to the order of several 100’s of microns along either axis of the beam, and the results discussed here represent roughly an order of magnitude improvement in that metric.