Excited state absorption processes in Sm3+ doped GdOCl

The FT-Raman spectrum of the polycrystalline GdOCl doped with 1 mol% Sm3+ 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:Sm3+ (x(Sm) = 0.06) and the energy level simulation of Sm3+ in SmOCl yielded the energy level scheme of Sm3+. The additional lines could be assigned to the IR and visible Stokes and anti-Stokes luminescence of Sm3+. Absorption of the 9400 cm(-1) photons lends first to transition to the F-6(9/2) and then to the F-4(3/2) energy level of Sm3+. The lines corresponding to luminescence at 13 596 and 12 310 cm(-1) could then be assigned to the anti-Stokes transitions from the F-4(3/2) energy level to the H-6(13/2) and H-6(15/2) levels, respectively. Also lines in the Stokes emission originate from the luminescence processes of Sm3+. However, all the extra lines in the Raman spectrum have not yet been explained by the luminescence processes. (C) 2000 Published by Elsevier Science S.A. All rights reserved.