Dielectric-Boosted Sensitivity to Cylindrical Azimuthally Varying Transverse-Magnetic Resonant Modes in an Axion Haloscope

Axions are a popular dark-matter candidate that are often searched for in experiments known as "haloscopes,"which exploit a putative axion-photon coupling. These experiments typically rely on transverse-magnetic (TM) modes in resonant cavities to capture and detect photons generated via axion conversion. We present a study of a resonant-cavity design for application in haloscope searches, of particular use in the push to higher-mass axion searches (above approximately 60μeV). In particular, we take advantage of azimuthally varying TMm10 modes that, while typically insensitive to axions due to field nonuniformity, can be made axion sensitive (and frequency tunable) through the strategic placement of dielectric wedges, becoming a type of resonator known as a dielectric-boosted axion-sensitivity (DBAS) resonator. Results from finite-element modeling are presented and compared with a simple proof-of-concept experiment. The results show a significant increase in axion sensitivity for these DBAS resonators over their empty-cavity counterparts and high potential for application in high-mass axion searches when benchmarked against simpler more traditional designs that rely on fundamental TM modes.