Luminescent crystals of MIIGa2S4:Er3+ (MII = Eu, Yb, Ca)

We have studied the photoluminescent properties of MIIGa2S4:Er3+ polycrystals (MII = Eu, Yb, Ca) for excitation by radiation with λ = 976 nm as a function of temperature. The samples were obtained by solid-state reaction. We have studied the comparative characteristics of the anti-Stokes and IR luminescence of these luminophores. We have determined the mechanisms for anti-Stokes emission of MIIGa2S4:Er3+ crystals.