High-frequency gravitational wave detection by the BREAD experiment

The use of experiments searching for light axion dark matter as high-frequency gravitational wave 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 by employing single photon detectors, BREAD is sensitive to GWs with characteristic strains as low as <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mn>10</a:mn><a:mrow><a:mo>−</a:mo><a:mn>21</a:mn></a:mrow></a:msup></a:math> at 0.1 THz and <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:msup><c:mn>10</c:mn><c:mrow><c:mo>−</c:mo><c:mn>25</c:mn></c:mrow></c:msup></c:math> at 200 THz with a year exposure time, making it competitive with other proposals operating at similar frequencies.