Effect of doping concentration on spectroscopic and structural properties of Nd:NaY(WO_(4))_(2) crystal

摘要

The optical and structural properties of NaNd_(x)Y_(1-x)(WO_(4))_(2) (NYW) single crystals grown from melt containing 1-10 at. percent of Nd have been investigated. Optical absorption, photoluminescence, x-ray diffraction, and x-ray florescence studies have been carried out on grown crystals. The crystal is found to exhibit a broad absorption peak of approx16 nm width at 806 nm for 6 at. percent of Nd doping. A decrease in fluorescence lifetime from 150 to 80 (mu)s with an increase in Nd~(3+) concentration is observed for 1.06(mu)m emission. Spectroscopic quality parameters ((OMEGA)_(4)/(OMEGA)_(6)) and quantum efficiency calculated from the above measurements and application of Judd-Ofelt theory are found to be 1.1 and 68percent, respectively. Structural analysis through Rietveld refinement of x-ray diffraction data showed that the oxygen sublattice of NYW is not affected by changes in Nd dopant concentration, though the lattice dimensions are found to increase proportionately. The study for the first time shows that the high doping levels do not introduce any strain into the lattice. As a consequence the optical quality of the crystal does not deteriorate at high doping levels. The selection of doping concentration is therefore solely governed by the decay time requirement for a particular application.