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Updated: Jun 20, 2026

Evanescent Field Based Photoacoustics: Optical Property Evaluation at Surfaces
Published on: July 26, 2016
Moiré signals by the photoacoustic effect
Abstract:
We report the detection of moiré displacement signals using the photoacoustic effect. By using the transmission and reflection (absorption) gratings with a 25microm pitch, the lateral displacement of the grating is detected from the photoacoustic signals. The probe-beam deflecton method and the microphone method are used for detecting the acoustic vibration and the acoustic pressure, respectively. The signals vary periodically as the pitch of the grating for the lateral displacement. The characteristics of the displacement signal are also examined by using the Fresnel diffraction theory.
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