Abstract:
Recent studies involving the properties of metallic nanostructures for potential technological applications are
fundamentally rooted in their optical absorption and scattering properties. In this study, we report the far-field
optical behavior of self organized copper (Cu) nanoripples on a glass substrate fabricated using low energy Ar+
ion beam irradiation for varying ion fluences. The optical characterization was performed by measuring the
specular as well as the diffuse component in wavelength dependent transmittance spectra for the irradiated
samples. Quantitative analyses has been performed on the morphology of the nanostructured films in order to
extract the surface statistical parameters like roughness, wavelength, aspect ratio and correlation length. Optical
responses from the nanostructured surfaces exhibit additionally strong characteristic spectra arising out of
diffuse scattering as compared to the specular ones for increasing incident ion fluences. The peak intensity and
sharpness observed in the transmittance spectra was found to depend largely on the surface height correlations
which showed variation with increasing ion fluences. Finally, we demonstrate the dependencies of the local
surface slope and the autocorrelation function in regulation of the optical transmittance of the nanoripple
structured Cu thin films.
