中文摘要：

利用等效介电常数法，将带壳三组分颗粒复合体系等效成两组分颗粒复合体系，从而利用谱表示方法求解带壳层颗粒复合体系的空间局域场对外加电场的依赖．在Maxwell—Garnett近似下，研究了具有无规分布的带壳椭球颗粒非线性复合体系中的光学双稳特性．数值结果表明，光学双稳和双稳阈值强烈依赖颗粒的退极化因子．此外。我们还研究了复合体系的有效介电常数对外场的非线性依赖．

英文摘要：

With the dielectric constant method, the dielectric response for three-phase composite media, in which coated inclusions are randomly embedded in a dielectric host, can be regarded as that of two-phase composites. As a resuh, we are able to obtain the dependence of the local field on the applied field based on the spectral representation theory. Then, we adopt the Maxwell-Garnett approximation to investigate optical bistability （OB） of three-component composites in which non-spherical coated inclusions are randomly embedded in a dielectric host in the dilute limit. Numcrical results show that the OB behavior is strongly dependent on the depolarization factor （L） of the particles. The field-dependent effective dielectric constant of the composites is also studied.