Excited state absorption processes in Sm 3+ doped GdOCl

Abstract

The FT-Raman spectrum of the polycrystalline GdOCl doped with 1 mol% Sm 3+ was measured at room temperature using a cw Nd:YAG laser with the excitation wavelength of 1064 nm (9400 cm −1). Besides the very weak Stokes and anti-Stokes Raman lines the additional strong lines were concluded to result from luminescence processes. The UV–Vis–NIR absorption spectra of GdOCl:Sm 3+ ( x Sm=0.06) and the energy level simulation of Sm 3+ in SmOCl yielded the energy level scheme of Sm 3+. The additional lines could be assigned to the IR and visible Stokes and anti-Stokes luminescence of Sm 3+. Absorption of the 9400 cm −1 photons leads first to transition to the 6F 9/2 and then to the 4F 3/2 energy level of Sm 3+. The lines corresponding to luminescence at 13 596 and 12 310 cm −1 could then be assigned to the anti-Stokes transitions from the 4F 3/2 energy level to the 6H 13/2 and 6H 15/2 levels, respectively. Also lines in the Stokes emission originate from the luminescence processes of Sm 3+. However, all the extra lines in the Raman spectrum have not yet been explained by the luminescence processes.