Journal or Book Title
Applied Physics Letters
Interference fringes due to bondline thickness variation were observed in ultrasonic scans of the reflected echo amplitude from the bondline of adhesively joined aluminum skins. To demonstrate that full-field interference patterns are observable in point-by-point ultrasonic scans, an optical setup for Newton's rings was scanned ultrasonically in a water immersion tank. The ultrasonic scan showed distinct Newton's rings whose radii were in excellent agreement with the prediction.
American Institute of Physics
Hsu, David K. and Dayal, Vinay, "Ultrasonic Newton's rings" (1992). Aerospace Engineering Publications. 47.