Anomalous polarized absorbance spectra of aligned Ag nanorod arrays

The polarized absorbance spectra of Ag nanorod array substrates with different lengths prepared by oblique angle deposition were studied in detail. An anomalous anisotropic absorbance was obtained which follows the relation alpha(theta)=-ln[A(1+B sin(2) theta)](beta), where theta is the polarization angle with respect to p-polarization direction. The exponent beta(< 0.5) is wavelength independent. This result cannot be interpreted by the conventional anisotropic effective medium theory, and the possible origin is the inhomogeneous size and orientation distributions that cause the variations in transmission and polarization.