Parametric excitation of temperature oscillations in a high-Q dielectric microwave resonator in liquid helium vapor

We study the threshold conditions of the parametric excitation of temperature oscillations using pulsed microwave pumping in three-mode regime for high-Q ferroelectric cryogenic resonators made of SrTiO₃ and KTaO₃. Comparative analysis is performed for the threshold power of the excitation of temperature oscillations and the threshold power of the ponderomotive parametric excitation of acoustic oscillations in the resonator. It is shown that in three-mode regime, temperature oscillations can develop under a rather moderate pump power of about 0.1–8 μW, depending on the combination of interacting temperature and electromagnetic modes. The calculated low threshold powers allow one to apply resonators in practice as high-sensitivity infrared sensors, resonant bolometers, and parametric amplifiers. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 52, No. 2, pp. 172–180, February 2009.