Analytical and numerical investigation of forward and inverse problems of light scattering by irregularly-shaped particles

Many applications require characterization of light scattering by nonspherical particles, since most natural particles have nonspherical geometries. The development of accurate, yet easy-to-use, inversion-enabling approximations to model light scattering by nonspherical particles is of critical importance. Previously, we introduced the concept of "equiphase sphere" for characterizing light scattering from nonhomogeneous and nonspherical particles of sizes in the resonance range (Chen, Z. et al., Opt. Lett., vol.28, no.10, p.765-7, 2003; J. Opt. Soc. America, vol.A20, no.1, 2004). We now report novel analytical approaches based on the modified Wentzel-Krammers-Brillouin (WKB) and equiphase-sphere (EPS) methods that enable accurate characterization of light scattering by a wide range of irregularly-shaped dielectric particles. We also demonstrate the potential of using these approaches to address the inverse-scattering problem by successfully probing the sizes and geometric characteristics of arbitrarily-shaped particles using their total-scattering-cross-section (TSCS) spectra.