Axion search on a chip

Abstract

Axions and axion-like particles are well motivated candidates for dark matter and have a signature two photon vertex. The most sensitive axion dark matter search is at the gigahertz regime, which relies on microwave cavities with high quality factors resonantly converting axion dark matter to cavity photons in the background of a static magnetic field. However, axion dark matter mass could span a vast range above or below gigahertz. We describe a new proposal using integrated/on-chip photonic systems to search for axion dark matter at the optical frequency. This enables the use of waveguides to collect signal photons, which improves the detection efficiency, as well as the use of single photon, micron-sized detector, such as a charge-coupled device (CCD), which has a dark count as low as 1e−9 per pixel per second. Furthermore, due to the small scale of the experiment, a static magnetic field as large as 40 Tesla can be employed. Our setup also provides a broadband detection in terms of axion masses and has sensitivities to axion photon couplings expected for QCD axion with a mass of around 1eV.