CHARACTERIZING INTERNAL STRUCTURES VIA ULTRASOUND

The present disclosure provides for characterizing internal structures via ultrasound by inducing an ultrasonic test wave in a component; developing a test signature based on measured propagation of the ultrasonic test wave through the component; characterizing an internal feature of the component based a comparison between the test signature and a baseline signature for the component; and providing an indication of the internal feature as characterized. In some aspects, the ultrasonic test wave is induced by a laser inducer and/or received by a laser interferometer. The test signature includes one or more of: frequency responses, amplitude responses, and times of flight. The test signature can be used to identify changes in a component over time, verify similarity between different components, monitor thermal processes, and verify an identify of a component.