TRANSPARENT TELLURITE-BASED GLASS-CERAMICS WITH 2ND-HARMONIC GENERATION

Transparent glass-ceramics, in which the crystalline phase has basical ly a face centered cubic structure, have been prepared in the system K 2O-Nb2O5-TeO2, and a second harmonic generation (SHG) is observed. The second harmonic intensity in the glass-ceramics is comparable to that in electrically poled TeO2-based glasses. A very small distortion fro m the cubic structure might be present and an origin of SHG. Transpare nt glass-ceramics consisting of the cubic crystalline phase have been also fabricated in the system of Li2O or Na2O-Nb2O5-TeO2, but SHG is n ot observed.