Infrared to visible and ultraviolet upconversion processes in Nd 3+-doped potassium lead chloride crystal

Abstract

Infrared to visible and ultraviolet upconversion in Nd3+ doped KPb2Cl5 crystal is reported. Three intense bands have been observed at 535, 595, and 668 nm coming mainly from levels 4G 7/2-4G9/2, together with emissions at 362, 388, 420 and 456 nm coming from level 4D3/2, and a peak at 435 nm, corresponding to the 2P1/2→4I 9/2 transition. A study of the upconversion mechanisms has been carried out that includes the upconversion emission dependence on the wavelength and intensity of the pumping light together with a comparison of the luminescence decays after infrared excitation and after direct one photon excitation of the emitting levels. The results indicate that two- and three-body energy transfer upconversion processes are responsible for emissions from levels 4G7/2-4G9/2 and 4D3/2 respectively, while level 2P 1/2 is populated by either energy transfer upconversion or excited state absorption depending on the pumping wavelength. © 2004 Elsevier B.V. All rights reserved.