Abstract
Physical Optics Approximation is used to compute scattering efficiency factors forward- and back-scattering intensities, angular distributions of intensity and depolarization by large dielectric or absorbing spheroids. The results are compared with those obtained by exact theories or other approximate calculations. If the radius of curvature at any point of the illuminated part of the scatterer is greater than about a few wavelengths, that approximation is generally the best one and in good agreement with the exact theories. This curvature requirement depends on the size of the spheroid but also on its orientation with respect to the incident light direction.