Pramodini, S.Aravinda, L.S.Nagaraja, K.K.Poornesh, P.2026-02-052021Optics and Laser Technology, 2021, 142, , pp. -303992https://doi.org/10.1016/j.optlastec.2021.107182https://idr.nitk.ac.in/handle/123456789/23062Herein, we report on the nonlinear optical studies on the nano colloidal solutions of titanium dioxide (TiO<inf>2</inf>), TiO<inf>2</inf>-dye and acid blue dye in distilled water under continuous wave laser using the z-scan technique. The phase and structural properties of the sol–gel synthesized TiO<inf>2</inf> nanoparticles at different temperatures were analyzed by x-ray powder diffraction (XRD) studies. The transmission electron microscopy (TEM) images confirmed that with an increase in calcination temperature, crystallite size increases. Further, the Fourier transform infrared (FTIR) spectra validate the synthesized TiO<inf>2</inf> nano particle's structure. The results from the z-scan reveal self-defocusing and reverse saturable absorption (RSA) behaviors of nano colloidal. The real and imaginary parts of third-order nonlinear optical susceptibility ?(3) were determined and estimated as 10?6 esu. Also, the optical limiting behavior of the samples is studied; a clamping of around ~ 4 mW is observed for the TiO<inf>2</inf>-dye nano colloidal. © 2021 Elsevier LtdContinuous wave lasersCrystallite sizeFourier transform infrared spectroscopyHigh resolution transmission electron microscopyNonlinear opticsSolsSynthesis (chemical)TiO2 nanoparticlesX ray powder diffractionColloidal solutionsContinuous-wave lasersCW-laserNonlinear optical studiesOptical limitingSynthesisedThermal nonlinearitiesTiO$-2$Titania dioxide (TiO2)-dye nano colloidalZ-scanTitanium dioxide