A Feasibility Study on Generation of Acoustic Waves Utilizing Evanescent Light

3rd International Symposium on Laser Ultrasonics and Advanced Sensing

Matsuya, I.^1 ; Matozaki, K.^2 ; Kosugi, A.^2 ; Ihara, I.^1

Department of Mechanical Engineering, Nagaoka University of Technology, Kamitomioka 1603-1, 940-2135 Japan Nagaoka, Niigata, Japan^1

Graduate School of Engineering, Nagaoka University of Technology, Kamitomioka 1603-1, 940-2135 Nagaoka, Niigata, Japan^2

关键词: Evanescent light;    Exponential decays;    Feasibility studies;    Incident angles;    Laser ultrasonic techniques;    Near field optics;    Pulsed Nd:YAG laser;    Total internal reflections;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/520/1/012003/pdf
DOI  :  10.1088/1742-6596/520/1/012003

来源: IOP

【 摘 要 】

A new approach of generating acoustic waves utilizing evanescent light is presented. The evanescent light is a non-propagating electromagnetic wave that exhibits exponential decay with distance from the surface at which the total internal reflection of light is formed. In this research, the evanescent light during total internal reflection at prism surface is utilized for generating acoustic waves in aluminium and the feasibility for ultrasonic measurements is discussed. Pulsed Nd:YAG laser with 0.36 J/cm2power density is used and the incident angle during the total internal reflection is arranged to be 69.0° for generating the evanescent light. It has been demonstrated that the amplitude of the acoustic waves by means of evanescent light is about 1/14 as large as the one generated by the conventional pulsed laser. This reveals the possibility of using a laser ultrasonic technique with near-field optics.