Third order nonlinearity of PMMA/ZnO nanocomposites as foils.

Nonlinear optical properties have received great interests by experimentalists due to a wide range of applications in the optical devices. In the current work, the polymethyl methacrylate (PMMA)/ZnO nanocomposites have prepared as foils by using casting method. Nanocomposites have prepared by mixing the different concentrations of ZnO nanoparticles as filler with PMMA as polymer matrix. Linear transmittance spectra have investigated and linear absorption coefficients have calculated. The nonlinear refractive index and nonlinear absorption coefficient have explored by using a single beam z-scan technique, Q-switched Nd-YAG pulse laser use as the light source. The transmittance shows decrease with the increase of the ZnO nanoparticles concentration. The samples have shown peak absorption at 375 nm. The nonlinear refractive index is in the order of 10 cm/W with the negative sign, whereas the nonlinear absorption coefficient is in the order of 10 cm/W. The real, imaginary parts and absolute value of the third-order nonlinear optical susceptibility χ have calculated. χ is in the order of 10 e.s.u. Hence, those nanocomposites indicate a promising candidate to be used as an optical limiter. [ABSTRACT FROM AUTHOR]