The study of the radiation patterns of laser-generated longitudinal ultrasound in semitransparent solid is presented.The experimental results are in good agreement with the theory based on the effect of optical penetr...The study of the radiation patterns of laser-generated longitudinal ultrasound in semitransparent solid is presented.The experimental results are in good agreement with the theory based on the effect of optical penetration within the sample.展开更多
The frequency spectrum of lascr-cxciicd ultrasonic wave has been measured in various metals including aluminum,sied and copper,at both fm and modified surfaces.The result shows that tke material and surface modificati...The frequency spectrum of lascr-cxciicd ultrasonic wave has been measured in various metals including aluminum,sied and copper,at both fm and modified surfaces.The result shows that tke material and surface modification affect the spectrum.展开更多
The effect of optical penetration on laser thermoelastically-generated ultrasound in non-metallic solids is studied theoretically on the basis of the thermoelastie equations. In one-dimensional model, on the assumptio...The effect of optical penetration on laser thermoelastically-generated ultrasound in non-metallic solids is studied theoretically on the basis of the thermoelastie equations. In one-dimensional model, on the assumption of some finite laser penetration, the general expression of wave displacement is obtaincd by solving the thermal diffusion and thermoelastic displacement equations, from which the influencc of optical absorption on the displacement amplitude is analyzed. In the case of two-dimensional axial symmetry, on neglecting the thermal diffusion, we solve the thermoelastic wave equation by means of the integral transform method and obtain analytic expressions of the wave displacement components in the far-field.Directivily patterns of both longitudinal and shear waves are presented and discussed.展开更多
基金Supported by the National Natural Science Foundation of China.
文摘The study of the radiation patterns of laser-generated longitudinal ultrasound in semitransparent solid is presented.The experimental results are in good agreement with the theory based on the effect of optical penetration within the sample.
文摘The frequency spectrum of lascr-cxciicd ultrasonic wave has been measured in various metals including aluminum,sied and copper,at both fm and modified surfaces.The result shows that tke material and surface modification affect the spectrum.
文摘The effect of optical penetration on laser thermoelastically-generated ultrasound in non-metallic solids is studied theoretically on the basis of the thermoelastie equations. In one-dimensional model, on the assumption of some finite laser penetration, the general expression of wave displacement is obtaincd by solving the thermal diffusion and thermoelastic displacement equations, from which the influencc of optical absorption on the displacement amplitude is analyzed. In the case of two-dimensional axial symmetry, on neglecting the thermal diffusion, we solve the thermoelastic wave equation by means of the integral transform method and obtain analytic expressions of the wave displacement components in the far-field.Directivily patterns of both longitudinal and shear waves are presented and discussed.
