Abstract:
The diffraction of ultrasonic radiation on an amplitude diffraction grating in the near-field area (Fresnel diffraction) has been studied. The effect of self-imaging of the grating (Talbot effect) has been detected for ultrasonic radiation at distances from the grating in the range from $z = 0$ to $z = 2L_{\mathrm{T}}$, where $L_{\mathrm{T}}$ is the Talbot length. The fractional Talbot effect, i.e., the ultrasonic image of the grating with the period $d/2$, has been observed.