Fig. 5From: Recent developments in photoacoustic imaging and sensing for nondestructive testing and evaluationOne representative application of silicon using PA technologies for NDT/E: PA A-line signals in ground silicon wafers with different damage depth [37]. The measured values of A+ and A− can be used to determine the subsurface damage depth. LIU signal, laser-induced US signals (i.e., PA signals)Back to article page