Beam profile measurements using light refractive tomography

Abstract

A method for reconstructing the sound pressure profile from interferometer measurements using computed tomography is presented. In accordance with the term light diffraction tomography, in short we want to call the method light refractive tomography, because it is based on the sound pressure-induced refractive index change along the laser beam. We compare three tomographic reconstruction methods applicable to axisymmetric beam profiles, namely, the filtered back-projection, the Hankel Fourier method, and the onion peeling method, the latter based on Nestor and Olsens algorithm. Results are compared to hydrophone measurements. The performance of the tomographic algorithms are reflected by general considerations on the reconstruction of noise signals.