Preparation and photoluminescence properties of RE:Na3La9O3(BO3)8 (RE=Er, Yb) crystals

Using Na 2 CO 3 –H 3 BO 3 –NaF as fluxes, transparent RE :Na 3 La 9 O 3 (BO 3 ) 8 (abbr. RE :NLBO, RE =Er, Yb) crystals have been grown by the top seed solution growth (TSSG) method. The X-ray powder diffraction analysis shows that the RE :NLBO crystals have the same structure with NLBO. The element contents were determined by molar to be 0.64% Er 3+ in Er:NLBO, 2.70% Yb 3+ in Yb:NLBO, respectively. The polarized absorption spectra of RE :NLBO have been measured at room temperature and show that both Er:NLBO and Yb:NLBO have a strong absorption bands near 980 nm with wide FWHM (Full Wave at Half Maximum) (21 nm for Er:NLBO and 25 nm for Yb:NLBO). Fluorescence spectra have been recorded. Yb:NLBO has the emission peaks at 985 nm, 1028 nm and 1079 nm and the emission peak of Er:NLBO is at 1536 nm. Spectral parameters have been calculated by the Judd–Ofelt theory for Er:NLBO and the reciprocity method for Yb:NLBO, respectively. The calculated values show that Er:NLBO is a candidate of 1.55 μm laser crystals and Yb:NLBO is a candidate for self-frequency doubling crystal.