uaser Richard Weaver Oleg Lobkis Alexey Yamilov We report theory, measurements and numerical simulations on nonlinear piezoelectric ultrasonic devices with stable limit cycles. It is shown that the frequency of auto-oscillation is affected by the presence of an acoustic cavity; these spontaneously emitting devices adjust their frequency to the spectrum of the acoustic cavity. It is also shown that the auto-oscillation can be entrained by an applied field; the oscillator synchronizes to an incident wave at a frequency close to the natural frequency of the limit cycle. Synchronization occurs with a phase that can, depending on details, correspond to stimulated emission such that the energy in the cavity is augmented. These behaviors are essential to eventual design of an ultrasonic system that would consist of a number of such devices entrained to their mutual field, a system that would be an analog to a laser. A prototype uaser is constructed. August 21, 1970 library/entrainment2.pdf uaser auto-oscillator paper 5 12 392976833 Richard Weaver This is a discussion of why we think the uaser is interesting. uaserauto-oscillatorwriteup August 21, 1970 library/Uaser.discussion.pdf 23 13 1758830466 Alexey YamilovRichard WeaverOleg Lobkis A brief and somewhat technical introduction to the uaser. uaserauto-oscillatorwriteup August 21, 1970 library/whywecallitauaser.pdf 24 14 1796273045