Parametric interaction of the electric and acoustic fields in a sapphire monocrystal transducer with a microwave readout

A sapphire monocrystal configured with a parametric microwave readout can p otentially monitor the motion of its internal acoustic resonances at the pr ecision governed by quantum mechanical fluctuations. The mechanism of trans ductance is due to parametric interaction between the electric and acoustic field within the crystal. This mechanism has been tested for the first tim e, and the theory has been verified by observing the pump frequency depende nce of the acoustic quality factor. Because of the extremely low acoustic l osses (Q>10(7)) and electrical losses (Q>10(4)), measurements were sensitiv e enough to attain positive verification at room temperature. (C) 1998 Amer ican Institute of Physics. [S0021-8979(98)04024-9].