An ultrahigh sensitivity sapphire transducer for vibration measurements

Sapphire dielectric resonator (SDR) transducers have been shown to achieve 10 -15 m Hz -1/2 sensitivity for vibration frequencies above 100 Hz by using an ultrastable sapphire loaded cavity oscillator as the pump source. This paper describes an interferometric transducer configuration which avoids the need for an ultralow noise oscillator, but maintains existing sensitivity. An initial performance of the transducer with the new configuration is presented.