Site-selective spectroscopy and infrared-to-visible upconversion in a Nd3+-doped Pb5Al3F19 crystal

In this work, we analyzed the spectroscopic features of the absorption and emission of Nd3+ in a fluoroaluminate Pb5Al3F19 crystal. Two main crystal held sites were identified for the rare earth in this crystal which may correspond to the two different crystallographic sites of Pb2+. Infrared-to-visible and -ultraviolet upconversion, under continuous wave and pulsed laser excitation, was observed at room and low temperatures. Analysis of the steady-state excitation spectra and of the decays of the upconverted emissions shows that the most likely mechanism for the observed upconversion emissions is an energy-transfer upconversion (ETU) process. (C) 2001 Elsevier Science B.V. All rights reserved.