High-Frequency Gravitational Waves on BREAD

Abstract: The use of light axion dark matter experiments as high-frequency gravitational wave (HFGW) detectors has garnered increasing attention in recent years. We explore the capabilities of the Broadband Reflector Experiment for Axion Detection (BREAD) in probing the GW parameter space and study the directional dependence of its coverage. This detector can investigate frequencies ranging from 0.05 to 200 THz. We find that employing single photon detectors BREAD is sensitive to GWs with characteristic strains as low as $10^{-21}$ at 0.1 THz and $10^{-25}$ at 200 THz with a year exposure time, making it competitive with other proposals operating at similar frequencies.