EN
The optical absorption, emission spectra and luminescence decay kinetics under photoexcitation of Gd_{3}Ga_{5}O_{12} (GGG) garnet epitaxial films doped with Cr^{3+} ions and co-doped with Cr^{3+} and Mg^{2+} ions have been investigated. Luminescence of the GGG:Cr films due to ^{4}T_{2} → ^{4}A_{2} and ^{2}E → ^{4}A_{2} transitions in Cr^{3+} ions have been observed. Increase of the activator ions concentration has an influence on the intensity and decay time of Cr^{3+} ions photoluminescence. Introduction of the magnesium ions leads to partial transformation of chromium valence state (Cr^{3+} → Cr^{4+}) and to the appearance of a broad absorption band with the maximum at 860 nm. The narrow lines with luminescence maxima at 704 and 706 nm have arisen in the highly doped GGG:Cr,Mg films.