Mie-scattering formalism for spherical particles embedded in an absorbing medium

Most of the Mie-scattering calculations have been done for a particle embed ded in a nonabsorbing host medium. Generalization to an absorbing host medi um can be achieved (a) by: modifying the calculation of the spherical Besse l functions to account:for a complex argument and (b) by accounting properl y for the net rate of incident, scattered, and absorbed energy. We present an extended formalism of Mie scattering for the case of an absorbing host m edium. Numerical calculations show that for a large spherical particle embe dded in an absorbing host medium the extinction efficiency approaches 1 com pared with 2 for a nonabsorbing host medium. We conjecture that this differ ence is due to the suppression of diffraction when the radius of the sphere is large. (C) 2001 Optical Society of America.