UNIDIRECTIONAL ULTRASONIC AMPLIFICATION IN A LASER-PUMPED MEDIUM

Abstract
Unidirectional parametric amplification of an ultrasonic wave propagating in a laser‐pumped birefringent medium was observed. Using x‐cut quartz pumped by a ruby laser, power gains approaching 10 dB were measured at ultrasonic frequencies in the neighborhood of 75 MHz. The effect was identified as a ``coflow''‐type parametric interaction.