Method for Identification of Optical Resonances of Metal Films

In this paper, the properties of thin (10–100 nm, R > 7 Ω) copper films deposited on glass substrates at T = 300 K are considered. The thin films were produced by thermal evaporation in a vacuum with residual gas pressure (10⁻²–10⁻³ Pa). The substrates had luminescence under exciting by Raman light (Raman scattering) of 30 mW power, with a wavelength of 785 nm. The resonances were identified by comparing the absorption and Raman spectra at excitation wavelengths of 633 and 785 nm. Among films with a close absorption level, films with the largest amplitude of the Raman signal had a structure with the maximum value of optical resonances. Under the influence of exciting light of 30 mW, the Raman spectrum and the color of these films changed. Copper films deposited on glass substrates at a temperature of 300 °C with an electrical resistivity R < 0.5 Ω/square did not have pronounced Raman peaks, their Raman spectrum and color did not change under 300 mW excitation light with a wavelength λ of 785 nm.