Abstract: The directivity of Gauss beam generated ultrasound in non-metallic solids are stutied theoretically. We solve the thermoelastic wave equations by means of the integral transform mathod and obtain analytic expressions of the wave displacements in the far-field. We also present directivity patterns of both longitudinal and shear waves, discuss the effects of optical absorption coefficient on the diretivity of the ultrasound waves and compare them with the experimental results.

Key words: directivty, laser generated ultrasond, relative optical absorption coefficient