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

Abstract

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 (Ca1-x-yYbxNay)Ga2O4 luminophore composition has been suggested at which the 993 nm luminescence intensity is the highest.