LOCAL FIELDS EFFECTS AND OPTICAL SUSCEPTIBILITY OF COMPOSITE MEDIA

摘要

The hierarchy of the different mathematical expressions for a macroscopic mixture of a two-component medium is classified in terms of the screening factor of inclusions. The importance of a proper choice of the mesoscopic local factor becomes evident from comparison with the exact results for 2D case and equal concentrations of the phases, i.e., the Dykhne formula for the effective permittivity of a two-phase film as the geometric mean permittivity (ε_aε_b)~(1/2) of the constituents. In addition, the macroscopic optical properties of doped media with embedded impurities are considered. By using the earlier developed generalized method of integral equations (GMIE) one can take into account the discrete nature of the impurities as well as that of the host medium and for the first time calculate a clustering effect of impurities in the host medium. This approach permits to account the microgeometry of the components for any solvable mesoscopic structure (Maxwell Garnett model, columnar geometry, etc.).