Analysis of the optical properties of Cu[([In.sub.1-x][Ga.sub.x]).sub.3][Se.sub.5] crystals

The analysis of the optical properties of bulk Cu[([In.sub.1-x][Ga.sub.x]).sub.3][Se.sub.5] mixed crystals prepared from the elements as a function of the Ga content is described. The values of the interband transitions are shown to increase linearly with the increasing Ga content.