Speaker
Description
Conventional closed resonator haloscopes become increasingly ineffective at probing axion masses above $\sim 40 \mathrm{\mu eV} $, as their effective volume scales as $V_\mathrm{eff} \propto 1/m_a^{3}$, leading to a steep decline in signal power with increasing mass. Open resonators, in contrast, relax the transverse boundary conditions, resulting in a more favorable scaling of $V_\mathrm{eff} \propto 1/m_a$. This can significantly improve sensitivity at higher axion masses, if diffractive losses are kept low.
In this talk, I will introduce the Fabry-Pérot Axion Experiment (FAxE), a proposed haloscope targeting axion dark matter in the 30–70 GHz range using a Fabry-P\'erot–type open resonator. FAxE is designed to achieve an effective volume on the order of $\mathcal{O}(10^3) \lambda^3$, while maintaining a high quality factor. This is enabled by a graded-phase mirror design, which suppresses diffraction losses more effectively than traditional spherical designs, without compromising mode volume.
I will outline the FAxE design concept, discuss simulation and prototyping results, and describe the key technical milestones required to achieve sensitivity at the level of the QCD axion in the targeted mass range.
