The advantages that laser based ultrasonic systems enjoy such as remote, non-contact applicability on complex-shaped structures in possibly thermally hostile environments, typically come with a price tag in terms of diminished sensitivity vis-a-vis conventional piezoelectric transducers. Much of the effort in developing laser ultrasonic systems over the past two decades has therefore been devoted to improving their performance. The signal-to-noise ratio of a shot noise limited laser interferometric detection system is given by (1): SNR propor. to U~2P_0/triangle openf (1)
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