Temperature dependences of the optical properties of aluminum nanoparticles

The spectral dependences of the optical properties of aluminum at various temperatures have been analyzed. We have proposed and tested the approximation expressions for the imaginary part of the dielectric permittivity. The reflection coefficients at normal incidence of light and the optical properties of nanoparticles with a radius of 150 nm in a temperature range of 298–933 K have been calculated for practically important wavelengths. The optical properties of aluminum are found to be atypical, with the absorption coefficient decreasing with increasing temperature. This is due to the contribution of interband transitions to the optical properties of aluminum.