Optical bistability in composite media with nonlinear coated inclusions

We study the intrinsic optical bistability in nonlinear composites of coated spherical particles with a metallic core and a nonlinear dielectric shell. By means of self-consistent mean field approximation, the relation between the local field in the core of inclusions and the external applied field is established. We demonstrate numerically that the optical bistability exists only when the interfacial parameter lambda is less than a critical one lambda(c). By the suitable adjustment of lambda in the range (0, lambda(c)), the threshold fields can be reduced substantially, and thus improve the potential applicability of this kind of material. The dielectric loss is found to reduce the optical bistability region due to the increase in the lower threshold field. Furthermore, the reflectance at normal incidence R is calculated, and the hysteresis loops are found also. (C) 2003 Elsevier B.V. All rights reserved.