Optical non-linearity of TiO2-containing glasses measured by Z-scan technique

The non-linear refraction and non-linear absorption of melt-derived and sol gel-derived TiO2-containing glass samples were investigated by the Z-scan technique. Primarily, the effects of composition and structure of glasses o n the non-linear refractive index (gamma) were measured. We found that a th ermo-optic effect is present in the measurements of gamma at TiO2 content < 25 mol%, and TiO2 component is the source of a positive Kerr effect at TiO2 content between 25 and 70 mol%, whereas it is the origin of a negative Ker r effect at TiO2 content >70 mol%. Consequently, we assumed that the sin in version of gamma around 25 mol% TiO2 in melt-derived samples is due to the change of dominant factor of gamma from thermo-optic effect to Kerr effect, whereas the sign inversion of gamma around 70 mol% TiO2 in sol-gel-derived samples may be due to the wavelength dispersion of gamma. (C) 1999 Elsevie r Science B.V. All rights reserved.