Growth, thermal and spectral properties of Tm~(3+), Ho~(3+) co-doped NaGd(MoO_4)_2 Crystal

摘要

A Tm~(3+)/Ho~(3+):NaGd(MoO_4)_2 crystal was grown by the Czochralski method. The XRD results matched standard data from JCPDS file, which accorded with scheelite structure with an 141/a space group. Thermal properties of crystal were analyzed by using the TG-DSC curve. The melting point and specific heat are 1182°C and 0.5 J/g K at 300 K, respectively. The Spectral properties of the Tm~(3+)/Ho~(3+):NaGd(MoO_4)_2 crystal were investigated, including room temperature absorption spectrum and fluorescence spectrum. The absorption cross-section of Tm~(3+) at 796 nm is 4.33×10~(-20)cm~2 with pertinent full widths at half maximum (FWHM) of 10 nm. The intensity parameters, spontaneous emission probability, fluorescence branching ratios and radiative lifetimes were calculated by Judd-Ofelt theory. The emission cross-sections are 1.47×10~(-20)cm~2 and 1.36×10~(-20)cm~2 for Tm~(3+) at 1850 nm and Ho~(3+) at 2000 nm respectively. The lifetime of ~5I_7 →~5I_8 (Ho~(3+)) was 4.263 ms.