MONOVALENT COPPER-ACTIVATED OXYGENATED INSULATORS

The photoluminescence of monovalent copper in oxygenated insulators ha s been extensively studied. The spectroscopy and the excited states dy namics of Cu+ ions were investigated as a function of the copper conce ntration and temperature in various glassy and crystallized materials, essentially berates and phosphates. The broad band fluorescences obse rved in the visible range under UV excitation arise from two main emit ting centers:isolated Cu+ ions and (Cu+)(2) pairs. The spectroscopic c haracteristics of isolated Cu+ depend strongly on the local structure, whereas those of the copper pairs remain nearly unaltered whatever th e host-matrix. Energy diagrams are proposed for both centers, using ab initio LCAO calculations, in connection with structural investigation s involving XRD, ND and EXAFS spectroscopies. Berate glasses can be co nsidered as potential laser sources for tunable output in the whole vi sible range.