IR luminescence of CaGa ₂O ₄ : Yb ³⁺ excited by 940 and 980 nm radiation

Existing calcium gallate CaGa₂O₄ based luminescent materials radiating in visible IR region have been reviewed. IR luminophores have been studied but slightly but their practical implementation is of interest. CaGa₂O₄ specimens activated with Yb³⁺ rare-earth ions have been synthesized using the solid-state method. The structure and luminescent properties of CaGa₂O₄ : Yb³⁺ have been studied. CaGa₂O₄ : Yb³⁺ excitation with 940 and 980 nm radiation generates luminescence in the 980–1100 nm region. Data on the electron level structure in Yb³⁺ ions suggest that the excitation and luminescence occur directly in the Yb³⁺ ions with only a passive role of the base lattice. The luminescence spectra contain three peaks at 993, 1025 and 1080 nm. These luminescence peaks are caused by electron optical transitions from excited to main state in Yb³⁺ ions. 993 nm band luminescence intensity has been studied as a function of Yb³⁺ activator ions concentration. Introduction of Na⁺ ions into the luminophore increases IR luminescence intensity. Optimum (Ca_1-x-_yYb_xNa_y)Ga₂O₄ luminophore composition has been suggested at which the 993 nm luminescence intensity is the highest.