Rare-earth doped low silica calcium aluminosilicate glasses for near and mid Infrared applications

The combination of properties such as chemical durability, transformation t emperature, thermo-mechanical properties, refractory properties, phonon ene rgy of about 800 cm(-1) and infrared transparency up to 6 mu m, recommend l ow silica (<7 wt%) calcium aluminosilicate glasses as hosts for laser appli cations. We have been investigating the physical properties of these glasse s prepared by melting under vacuum conditions. This preparation procedure e nsured minimum in OH content in the low silica calcium aluminosilicate glas s hosts with fluorescence quantum efficiency of about 0.92 and 2.8 mu m pho toluminiscence, in samples co-doped with Er and Yb. In this paper, we revie w the thermal, mechanical and optical properties of these minimum OH conten t rare-earth-doped oxide glasses and discuss their potentials for near- and mid-infrared applications. Particular emphasis is given to the discussion of the new and promising optical properties of Er-Yb doped samples for biom edical applications. (C) 2000 Elsevier Science B.V. All rights reserved.