DEPOLARIZATION OF LIGHT BACKSCATTERED BY RANDOMLY ORIENTED NONSPHERICAL PARTICLES

We derive theoretically and validate numerically general relationships for the elements of the backscattering matrix and for the linear, del ta(L), and circular, delta(C), backscattering depolarization ratios fo r nonspherical particles in random orientation. For the practically im portant case of randomly oriented particles with a plane of symmetry o r particles and their mirror particles occurring in equal numbers and in random orientation, delta(C) = 2 delta(L)/(1 - delta(L)) Extensive T-matrix computations for randomly oriented spheroids demonstrate that , although both delta(L) and delta(C) are indicators of particle nonsp hericity, they cannot be considered a universal measure of the departu re of particle shape from that of a sphere and have no simple dependen ce on particle size and refractive index.