Spectroscopic properties and energy levels of Yb3+ ion in huntite structure

Temperature dependence of Yb3+ optical absorption spectrum has been studied in crystals YbxTm1−xAl3(BO3)4 (x = 0.1, 0.2 and 1) in the temperature range 1.7-293 K. The spectra of the crystals appeared to be practically identical for the studied ytterbium concentrations. Raman scattering spectrum of YbAl3(BO3)4 crystal has been measured. Group theory analysis of the optical absorption spectra is made, and new energy structure of the ground and excited states of Yb3+ ion, based on the experimental data obtained, is presented. Transformation of the local environment of Yb3+ ion depending on temperature has been found out. Spectrum of luminescence has been calculated from the absorption spectrum by reciprocity method with the use of the proposed energy structure.