Superconducting Parallel-Plate Resonators for the Detection of Single Electron Spins
arXiv:2603.25258
Abstract
We introduce a multilayer superconducting microwave resonator with sub-Ohm impedance optimized for high coupling strength to single electron spins. The design minimizes the magnetic far-field and therefore achieves a Purcell factor . We show several ways to fabricate this type of resonator and present resonators with an intrinsic -factor exceeding at the single-photon level. We further characterize these resonators in magnetic fields up to . Finally, we evaluate the impact of the achievable Purcell factor on single-spin detection through photon counting and dispersive readout.
12 pages, 7 figures, plus supplementary material of 5 pages, 4 figures