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Progress of laser-generated ultrasonic non-destructive testing technology

Laser-generated ultrasonic non-destructive testing technology is a new cross-technology which utilizes lasers to excite and detect ultrasound, possesses the characters of complete non-contact, fast response, non-destruction, wide band range, high precision and low cost, can be used in some situations in which traditional piezoelectric ultrasonic testing is hardly applicable. In this paper, the fundamentals, application fields and development trend of laser-generated ultrasonic non-destructive testing technology are summarized. Firstly, the development and research situation of laser-generated ultrasonic non-destructive testing technology are introduced. Secondly, the laser-generated ultrasound excitation mechanism and ultrasound detection technology of laser-generated ultrasonic and are made a comprehensive review and summary. Finally, the main technical difficulties, future resolving direction and development trend of this technology are briefly analyzed. It is concluded that laser-generated ultrasonic testing technique will be applied more widely in the future, however, revealing the mechanism of laser-generated ultrasound and improving photoacoustic conversion efficiency and detection sensitivity are the key for the successful application of the technology, and also a focus of present research in this technical field.