FREE-ELECTRON ANALYSIS OF OPTICAL-PROPERTIES OF THERMALLY EVAPORATED GOLD-FILMS

Gold films of thicknesses 150-300 Angstrom were deposited on quartz su bstrata using vacuum evaporation technique. Spectrophotometric measure ments of transmission T and reflection R at normal incidence were perf ormed in the range 0.4-3.0 mu m. The real and imaginary parts of the c omplex refractive index (n) over tilde were determined using a develop ed algorithm based on Murmann's exact equations. The accuracy in the d etermined n and k was found to be +/-6.0% and +/-1.6%, respectively. T he dispersion curve of n showed an anomalous dispersion in the visible region characterized by a peak at lambda = 0.840 mu m. The dielectric constants were calculated and presented. The Drude model parameters o mega(p) and omega(tau) and d.c. conductivity were determined and compa red. The results showed that such parameters could be obtained from fr ee-electron analysis for the near IR experimental results and the intr aband transition contributes significantly to the dielectric functions .