Spectroscopic properties of OH− doped and Bi-rich Bi4Ge3O12 crystals by vertical Bridgman method

► Emission spectrum of Bi-rich BGO has extra peaks at 385, 367 and 357 nm. ► Bi-rich BGO after annealing shows emission at around 1170 nm under 808 nm LDs excitation. ► OH doped BGO shows emission band centered at about 1346 nm under 980 nm LDs excitation.