Geometrical-optics solution to light scattering by droxtal ice crystals

We investigate the phase matrices of droxtals at wavelengths of 0.66 and 11 mum by using an improved geometrical-optics method. An efficient method is developed to specify the incident rays and the corresponding impinging points on the particle surface necessary to initialize the ray-tracing computations. At the 0.66-mum wavelength, the optical properties of droxtals are different from those of hexagonal ice crystals. At the 11-mum wavelength, the phase functions for droxtals are essentially featureless because of strong absorption within the particles, except for ripple structures that are caused by the phase interference of the diffracted wave. (C) 2004 Optical Society of America.