ANISOTROPIC DIELECTRIC-CONSTANTS OF BI2SR2(CA1-XYX)CU2O8-CRYSTALS IN 0.5-5.0-EV REGION(Y (X=0.0, 0.6) SINGLE)

We have measured the reflectance spectra of the (001) surface of singl e crystals of Bi2Sr2(Ca1-xYx)CU2O8+y (x=0.0, 0.6) with polarized light from 0.5 to 5.0 eV. We have successfully obtained the anisotropic die lectric constants for a-, b- and c-axis directions separately with an original analysis using Fresnel's formula in which the anisotropy of t he crystal is considered. We report the method of analysis and the res ults, We discuss the anisotropy of tile dielectric constants and attem pt, to determine the origin of some absorption peaks. We compare the s pectra for two types of samples with different carrier concentrations.