Thulium optical centers in Tm,Nb:SrMoO4 crystal

Formation of three types of thulium optical centers is observed in SrMoO4 crystal doped with Tm3+ in the form of thulium niobate. Two types of optical centers are found to have quite similar spectroscopic properties, while the third one is characterized by richer absorption and fluorescence spectra and a twice shorter 1G4 level lifetime.