Effect of Yb3+ ion on Raman and absorption spectra of Er:Yb:YCa4O(BO3)3 crystals

Raman-scattering investigations in two crystals, Er:Yb:YCa4O(BO3)3 (EYYCOB) and Er:YCa4O(BO3)3 (EYCOB), show that the Yb3+ ions doped in the crystal largely change the crystal Raman spectra especially those of the Raman tensor elements αXX, αZZ, αXY, and αYZ, which imply the better nonlinear optical properties possible for this crystal as a nonlinear optical material, and these Yb3+ ions due to their influence on the symmetry of some Rare-earth (RE)-O octahedra also change their ligand field, which imply the better laser properties possible for this crystal as a laser material. These Raman measurements also show that the characteristic spectra of the crystals is mainly contributed by the BO3 triangles and partly by the Ca(1)O6 octahedra, which imply that the structural rigidity of the crystals is mainly ascribed to the BO bond stretching and bending and partly by the Ca(1)O bonds. On the basis of Judd–Ofelt theory, the effect of the sensitizing Yb3+ ions on the absorbance is analyse by comparing with the absorption spectra of EYYCOB and EYCOB. The spectral parameters around the pumping wavelength of an InGaAs diode laser and the luminescence parameters at about 1500 nm also are calculated for the crystal EYYCOB. These indicate that the crystal EYYCOB as a nonlinear optical and laser material would be excellent especially the radiation laser around 1500 nm to be desirable.