Optical absorption and fluorescence spectral studies of Sm ³⁺ ion in BaO-M <sub/>2</sub> O <sub/>3</sub> (M = Ga, Al, In)-P <sub/>2</sub> O <sub/>5</sub> glass systemsPrasad, S V G V A; Rao, B Lakshmana · IOP Conference Series: Materials Science and Engineering · 2009