A METHOD OF ULTRASONIC WAVE RECONSTRUCTION BASED ON INFORMATION CONTAINED IN THE NEAR-FIELD OF THE DIFFRACTED LIGHT

A method of ultrasonic field reconstruction is presented based on the light intensity distribution within the near field. It is shown that t he formulae derived according to the simplified Raman-Nath theory of l ight diffraction by an ultrasonic wave are the same as those developed by Blomme et al. in their method of reconstruction, except that they differ by a constant. The experimental results obtained for an ultraso nic field consisting of a fundamental tone and the second harmonic, co nfirm the theoretical investigations with good agreement.