Monolithic sapphire parametric transducer operation at cryogenic temperatures

The operation of a novel monolithic sapphire transducer from room temperatu re to cryogenic temperature is presented. The transducer is a microwave sap phire resonator that senses the motion of internal acoustic resonances thro ugh the interaction between electric and acoustic fields. The system is non contacting and has low mechanical and electrical losses. Also, the microwav e characteristics of sapphire are used as an inherent temperature sensor. H igh mechanical quality factors of 10(8) and 4.5 x 10(8) were attained at 30 0 and 4 K, respectively. (C) 2000 American Institute of Physics. [S0034-674 8(00)03707-2].