Upconversion Fluorescence Spectroscopy In Rare Earth Doped Sol-Gel Nano-Glass Ceramics

摘要

There has recently been a great deal of interest in searching for new materials for application as hosts in infrared-to-visible light upconverters or optical amplifiers based upon rare-earth doped systems. Some of their many applications include: color displays, high density optical recording, biomedical diagnostics, infrared laser viewers and indicators, fiber lasers and amplifiers. Fluorosilicate based sol gel glass ceramics have recently emerged as auspicious candidates for such photonic devices applications. These glasses are advantageous because they present low temperature of preparation, better mechanical strength, chemical durability, and thermal stability than fluoride-based glasses. The present work involves the investigation of optical transitions and upconversion fluorescence spectroscopy of trivalent lanthanide ions Er~(3+) codoped with Yb~(3+) in β-PbF_2 nanocrystals dispersed in silica glassy matrix, excited with near-infrared diode lasers. The dependence of the upconversion luminescence upon diode laser power, and the upconversion excitation mechanisms involved are also investigated.