Dependence of the optical activity of nano-sculptured copper thin films on the structural parameters and the dispersion of the dielectric function

Influence of the structural parameters (namely, angle of rise, half structural period, volume fraction of metal inclu-sion, columns shape factor, thickness) and the dielectric dispersion function on the optical activity of axially excited chiral nano-sculptured copper thin films are investigated for both s and p linearly polarized lights, using Bruggeman homogenization formalism in conjunction with the experimentally available relative dielectric constants for the bulk copper. It is observed that for both s and p polarizations the maximum of optical activity shifts towards longer wavelengths with increasing the half structural period, volume fraction of metal inclusion and the film thickness, while it shifts towards shorter wavelengths with increasing the transverse aspect ratio of the columns. The circular Bragg phenomenon is clearly observed when the angle of rise increased from 20° to 45°. Comparison of spectral results shows that the dispersion of the dielectric function has a considerable effect on the results.