Alberto Ghirri is involved in a new preprint concerning “Coupled resonators based on high permittivity dielectrics for microwave sensors”, which is now available on arXiv (arXiv:2410.05831) .
Here’s the abstract: “The use of coupled cavities with high quality factor is of undoubted interest for several applications including those concerning quantum sensing and metrology. Here we report on a coupled cavity configuration in which a high Q-factor elliptical TESLA-shaped superconducting cavity is coupled with a high permittivity (εr) dielectric resonator. We carried out first tests using a SrTiO3 (STO) resonator at 0.1 GHz, whose permittivity has been observed to reach values higher than 30000 a 0.16 K. The sensitivities of such configurations are discussed both in strong coupling and weak coupling regime. In particular we show that the notch of the coupled system has, as a function of the permittivity, a frequency sensitivity of 2.8 MHz for εr≈230. These results highlight the potential of the coupled resonator systems as microwave sensors and are useful for the engineering of high permittivity resonators for applications at cryogenic temperatures.“