FLUORESCENCE FROM HIGHLY-DOPED ERBIUM FLUOROZIRCONATE GLASSES PUMPED AT 800 NM

A study of the fluorescence properties, under 800 nm excitation, of ne w ZBEAN glasses with Er3+ concentrations up to 18 mol% is reported. Th is represents the highest reported doping concentration for this type of glass. The fluorescence intensity at 550 nm, 1.53 mu m and 2.7 mu m did not exhibit the expected strong quenching at these high concentra tions and the corresponding decay times were consistent with this obse rvation. Cooperative energy transfer between the relevant levels is di scussed as a possible explanation of this behaviour.