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An attempt has been
made to clarify the anisotropy in the optical absorption
and nanostructure of thin films prepared by oblique
codeposition of Ag and insulator(SiO2
or Ta2O5 ). At a low concentration
of Ag, the columnar structure grows toward the incident
direction of vapor flux of insulator, and Ag is
dispersed in that structure as small metallic particles.
The optical transmittance is strongly dependent
on the angle of incidence of the light, the degree
of polarization of incident light and the refractive
index of insulator. These properties can be mainly
interpreted in terms of the plasma resonance of
the free electrons in the small Ag particles embedded
in the biaxial matrix. Furthermore, an inhomogeneous
distribution of Ag is deposited from the side of
the normal to the film surface opposite to that
of the incident direction of the insulator. As the
result, the optical anisotropy is enhanced, and
useful polarization and angular selective properties
have been achieved. The anisotropic optical absorption
of metal and insulator hybrid films can be used
as an inorganic polarizer.
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