Morphology dependent dispersion of third-order optical nonlinear susceptibility in TiO2

Nanostructured TiO₂ in different shapes such as nanosheet, nanowire, and nanoflower, as well as nanosphere have been prepared and characterized. Nonlinear optical (NLO) properties were measured at 532 nm using open and closed aperture Z-scan technique with respect to the shape. NLO behaviour of the nanostructured TiO₂ is found to be shape dependent in suspensions at the investigated wavelengths and is accounted in terms of effective surface-to-volume ratio of the structures. The values of different optical constants viz, β,n ₂,χ ⁽³⁾ for different morphological structures were evaluated and compared. The optical limiting thresholds of the samples were also investigated and it is found to decrease with increase in the net light matter interaction area of the sample.