Effective-medium theory of a nonlinear composite medium using the<i>T</i>-matrix approach: Exact results for spherical grains

Abstract

An effective-medium theory for nonlinear spherical particles embedded in a linear host medium is developed. The formulation is based on a T-matrix approach. Introduction of a field-dependent T matrix enables one to obtain an exact expression for effective dielectric constant of a medium with spherical grains. In the special cases of low-field values, the results obtained previously for the third- and fifth-order nonlinear susceptibilities of the medium are recovered. The resonance behavior of the effective dielectric constant and intrinsic optical bistability are also discussed.