Site-selective spectroscopy of Nd3+ ions in heavy metal oxide glasses

Site-selective spectroscopy and time resolved fluorescence line narrowing e xperiments were performed on the F-4(3/2) --> I-4(9/2), I-4(11/2) transitio ns of Nd3+ in six different compositions of heavy metal oxide glasses based on Bi2O3, GeO2 and PbO. In all samples, a line-narrowing of the F-4(3/2) - -> I-4(11/2) emission has been observed when exciting at the long wave side of the I-4(9/2) --> F-4(3/2) transition. The lifetimes of the F-4(3/2) Sta te do not show a monotonic variation with the excitation wavelength indicat ing site-to-site variations in the local crystal field. Spectral migration of excitation among the Nd3+ ions has been studied from the time evolution of the F-4(3/2) --> I-4(9/2) spectra under resonant excitation. The results are interpreted in terms of a dipole-dipole transfer mechanism. (C) 1999 E lsevier Science B.V. All rights reserved.