Temperature dependent blue second harmonic generation in Ba5Li2Ti2Nb8O30 microcrystals embedded in TeO2 glass–matrix

The as-quenched samples in the system (100 − x) TeO2-(x) Ba5Li2Ti2Nb8O30 (2 ⩽ x ⩽ 8) were found to be embedded with 10–20 μm sized crystallites of the polar phase Ba5Li2Ti2Nb8O30 (BLTN). Blue (400 nm) second harmonic generation (SHG) was observed in transmission mode when 800 nm laser light was allowed to pass through the individual crystallites. The blue SHG signal was temperature dependent and its intensity was maximum at ∼175 °C which was tentatively attributed to the concomitant changes associated with the refractive indices of the BLTN crystallites. The SHG intensity attained a minimum value around the Curie temperature of BLTN crystals.