Preparation and up-conversion luminescence properties of Er: YbAG and Er: YAG single crystals

High quality optical single crystals of cubic Yb2.96Er0.04Al5O12 and Y2.96Er0.04Al5O12 were successfully prepared using the OFZ method. The 980 nm photon absorption intensity by Yb2.96Er0.04Al5O12 crystal is much larger than that in Y2.96Er0.04Al5O12 crystal, the transmission of Yb2.96Er0.04Al5O12 crystal is lower than that of Y2.96Er0.04Al5O12 crystal, because the density of Yb2.96Er0.04Al5O12 single crystal (6.604 g/cm3) is larger than that of Y2.96Er0.04Al5O12 single crystal (4.529 g/cm3). The up-conversion luminescence spectra of the crystals excited by 980 nm laser show several distinct groups of emission peaks at ∼544 and ∼556 nm, as well as ∼650 and ∼667 nm. The peak intensities of the up-conversion luminescence spectrum for the Yb2.96Er0.04Al5O12 crystal were much higher than those for the Y2.96Er0.04Al5O12 crystal. Overall, the results of the present study suggest that Yb2.96Er0.04Al5O12 single crystal may have advantages over Y2.96Er0.04Al5O12 single crystal for luminescence in solid-state lasers.