Defect reconstruction by non-destructive testing with laser induced ultrasonic detection

•Ultrasound generation and detection using hybrid method, a remote tool for NDT.•Laser generated ultrasound for volume reconstruction of embedded defects in metals.•Hybrid approach combines advantages of both photonic and ultrasonic devices.•Scanning large areas with LGU and fewer receivers, advantage for remote testing.•B-scan, SAFT using hybrid system provide higher resolution 3D imaging of defects. This work envisages a detailed study of two-dimensional defect localization and reconstruction, using laser generated ultrasound and its application as a remotely controlled non-destructive testing method. As an alternative to full ultrasonic or full optical approaches, we propose a hybrid configuration where ultrasound is generated by impact of laser pulses, while the detection is done with conventional transducers. We implement this approach for defect reconstruction in metallic elements and show that it combines advantages of both photonic and ultrasonic devices, reducing the drawbacks of both methods. We combine our experimental results with a high-resolution signal processing procedure based on the synthetic aperture focusing technique for the benefit of the final two-dimensional visualization of the defects.