Crystal Structure and Judd–Ofelt Analysis of Er^3+ Doped LuAl_3(BO_3)_4 Crystal

Single crystal Er:LuAl_3(BO_3) (Er:LuAB) is successfully grown using the top-seeded solution growth method with a K_2Mo_3O_10 flux. The cell parameters of the grown crystal are estimated by an x-ray single crystal diffactometor and x-ray powder diffraction analysis. The result indicates that it still belongs to the space group R32. The obtained unit-cell parameters are a=9.2793(19) Å, c=7.210(3) Å, V=537.65(27) Å^3, and Z=3. The absorption spectrum is measured at room temperature. The spectroscopy properties are investigated based on the Judd–Ofelt (J-O) theory, and the effective J-O parameters were calculated to be \it \Omega_2=8.33\times10^-20, \it \Omega_4= 3.83\times10^-20, and \it \Omega_6=3.55\times10^-20. The emission spectra of Er:LuAB crystal at room temperature are also studied and the ^4I_11/2\to ^4I_13/2 fluorescence around 3170 nm is observed. The emission cross section calculated by the F-L formula is 8.6\times10^-20 cm^2. These results suggest that the Er:LuAB crystal may be a promising \sim3 μm laser material.