Laser Ultrasonics for Detection of Elastic Nonlinearity Using Collinear Mixing of Surface Acoustic Waves

Review of Noncontact Ultrasonic Nondestructive Testing for the Solid Materials

“…Especially in the fields of aerospace, energy and material industry and other high-tech concentration fields, these problems are particularly prominent. All these problems make the application of conventional ultrasonic NDT technology is extremely limited [1]. The fundamental reason is that the use of piezoelectric ultrasonic transducer in conventional ultrasonic testing technology.…”