“…Here, embedding grains or wires of a superconducting metal in a material transparent to microwave radiation provides the desired inhomogeneity of the magnetic field that enables the search for axion. Intended to perform a tunable broad band scan for axion at high-frequency, the Dark-photons & Axion-Like particles Interferometer (DALI) [13,14] incorporates a Fabry-Pérot (FP) resonator, composed of ceramic layers, instead of a resonant cavity, or rather than superconducting wire planes as adopted in Sikivie's approach. This set-up can extend the quest for the axion to a range of masses which remains poorly explored, in part since in the Sikivie's cavity-haloscope the resonant frequency, 𝜈 0 , scales inversely on size, or the distance between the movable dielectric rods used for tuning, 𝑑, in the form 𝜈 0 ∼ 𝑐/𝑑, 𝑐 being the speed of light; while the coherence volume, which boosts the output power, decreases accordingly, lowering the sensitivity.…”