Second harmonic generation in transparent KTiOPO4/SiO2 nanocomposite glasses prepared by the sol–gel method

Transparent bulk xKTP–(1−x)SiO2 nanocomposites, containing nanocrystalline KTiOPO4 (KTP) dispersed in silica glass matrix, were fabricated by the sol–gel method. The transmission properties of KTP/SiO2 have been measured between 2500 and 300 nm and show transmission of 30% at 0.532 μm and 60% at 1.064 μm. The nanocomposite glasses exhibit an UV cut-off at 350 nm. The second harmonic generation (SHG) was observed from xKTP–(1−x)SiO2 nanocomposites or glass-ceramics. The intensity of the SHG signal in the nanocomposites increases as a function of KTP concentration.