Optical constants of CuGa5Se8 crystals

Spectral dependence of the real ɛ₁(ω) and imaginary ɛ₂(ω) parts of the complex dielectric function, complex refractive index, absorption coefficient, and normal-incidence reflectivity of CuGa₅Se₈ crystals with slightly different Cu contents are modeled using Adachi's model for interband transitions. The results are in good agreement with the experimental data over the entire range of photon energies. The model parameters are determined using the simulated annealing algorithm.