Determination of the optical constants of non-spherical particles

Based on the complete radiative transfer equation, an inverse model has been developed to determine the optical constants of non-spherical particles. Combined with the T-Matrix theory and Kramers-Kronig (K-K) relations, the complex refractive indices of non-spherical particle are retrieved. The application range of the inverse model is investigated firstly, and the unique value range and multi-value range are thoroughly discussed. In order to validate the present model, the optical constants of the ellipsoidal fly-ash particles available in the references are selected as the 'true values', and the direct simulation of transmittivity in one-dimensional (1D) slab by Monte Carlo method are regarded as the 'experimental values'. Good agreement is obtained between the retrieved optical constants and the known 'true value'. The influence of measurement error on the inverse results is also investigated.