Three polarization reflectometry methods for determination of optical anisotropy.
Three novel methods for the determination of optical anisotropy are proposed and tested. The first, the special points method, may be applied to any uniaxially anisotropic medium and is based on the measurement of s- and p-polarized light reflectances under near-normal or grazing angles (or both) and of the Brewster angle. The second method is based on the use of the Azzam universal relationship between the Fresnel s- and p-reflection coefficients. For a flat surface and an isotropic medium, the Azzam combination of coefficients becomes zero and thus is independent of the incidence angle, whereas for a uniaxial or biaxial anisotropic sample it acquires a certain angular dependence, which may be used to determine the anisotropy of the sample. Finally, for those cases in which the anisotropy of the material of a film deposited on an isotropic substrate is itself of interest, a third method, the interference method, is suggested. This technique makes use of the different dependences of s- and p-polarized beam optical path-length changes on the variation of the angle of incidence.
Surdutovich
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GI
Departamento de Semicondutores, Instrumentos e Fotônica, Faculdade de Engenharia Elétrica e de Computacão, Unicamp, CEP 13083-970, Campinas São Paulo, Brazil.
Vitlina
R Z
RZ
Ghiner
A V
AV
Durrant
S F
SF
Baranauskas
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V