The velocity of sound in gases was measured, using an ultrasonic
wave train as a diffraction grating. The fundamental problems
involved in the optical technique are discussed. An apparatus utilizing
an objective lens of focal length 1.5 m and aperture f/20 was constructed
and used at an ultrasonic frequency close...
The application of laser generated ultrasonics was first
demonstrated in the mid-seventies and has shown good potential
when applied to isotropic materials. However, its use with
composite materials is still in the early stages of development.
This study explores the potential for application of laser
generated Rayleigh and Lamb waves...