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

The combination of properties such as chemical durability, transformation temperature, thermo-mechanical properties, refractory properties, phonon energy of about 800 cm(-1) and infrared transparency up to 6 mu m, recommend low silica (<7 wt%) calcium aluminosilicate glasses as hosts for laser applications. We have been investigating the physical properties of these glasses prepared by melting under vacuum conditions. This preparation procedure ensured minimum in OH content in the low silica calcium aluminosilicate glass hosts with fluorescence quantum efficiency of about 0.92 and 2.8 mu m photoluminiscence, in samples co-doped with Er and Yb. In this paper, we review the thermal, mechanical and optical properties of these minimum OH content 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 biomedical applications. (C) 2000 Elsevier Science B.V. All rights reserved.