Fluorescence properties of Nd3+: LiNbO3 sol-gel derived powders

Luminescence properties of Nd3+ doped (1, 2 and 3 mol%) LiNbO3 powders prep ared by a sol-gel process are reported in this paper. Infrared emission tra nsitions (F-4(3/2) --> I-4(9/2,) (11/2) (and 13/2)) of Nd3+ at 890, 1060 an d 1340 nm have been measured under the excitation of an Ar+ laser (514 and 488 nm) and it has been found that the 2 mol% Nd3+ has an intense emission compared with the other contents. An up-conversion violet (398 nm) emission (D-4(3/2) --> I-4(13/2) or P-2(3/2) --> I-4(11/2)) has been observed with a 583-nm excitation, which is a hypersensitive transition (I-4(9/2) --> (4) G(5/2)) of Nd3+ having a strong absorption at the yellow wavelength. Apart from a bright violet up-conversion emission, three other emissions at 342 ( (4)D(3/)2 --> I-4(9/2)), 373 (P-2(3/2) --> I-4(11/2) or D-4(3/2) --> I-4(13 /2)) and 464 nm (P-2(3/2) --> I-4(13/2)) have also been measured. The viole t up-conversion emissions have been explained using an energy level diagram . The structural details and particle sizes of Nd3+-dopcd LiNbO3 powders ha ve been investigated from the XRD spectral patterns and the SEM images. (C) 2001 Elsevier Science B.V. All rights reserved.