Third-order NLO properties of Zn porphyrins are correlated to their structures by combining experiments and DFT calculations adopting six strategies. Molecules of lesser π-electron conjugation are also shown to have higher NLO characteristics.

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This work reports a detailed study of the synthesis, characterization and third-order nonlinear optical properties of Ag and Al2O3 nanoparticles and their polymer nanocomposites. Ag and Al2O3 nanoparticles were prepared by the chemical precipitation method. The X-ray diffraction studies confirmed the purity and the crystalline nature of the sample and revealed the crystallite size. The linear optical properties and the structural morphology of the nanoparticles were confirmed using UV–visible spectroscopy and SEM analysis. The prepared nanoparticles were introduced into the polymer matrix by the spin-coating technique. Open-aperture and closed-aperture Z-scan technique was used to study the nonlinear absorption and nonlinear refraction of the samples under a Q-switched Nd:YAG laser at 532 nm. The observed third-order nonlinear optical susceptibility (χ(3)) was on the order of 10−6 esu, which indicates that these materials are potential candidates for photonic applications.

We report the third-order nonlinear optical properties of polyaniline doped with an azo dye synthesized using cardanol. Cardanol, which is distilled from CSNL (Cashew Nut Shell Liquid), is a renewable resource since it is a byproduct of the Cashew nut industry. The linear absorption spectrum of the sample was determined in the wavelength range 100 – 800 nm. FTIR spectroscopic data of undoped and azo dye-doped polyaniline samples were compared. The morphology and structure of the azo dye-doped polyaniline are studied using SEM images and XRD. Nonlinear absorption studies were carried out using the single beam z scan technique. A Q-switched Nd: Yag laser operating at 532 nm wavelength with a pulse width of 7 ns was used as the source of light. The nonlinear absorption coefficient and nonlinear susceptibility were determined to be of the order of 10−11 m/W and 10−11 esu respectively. The results indicate that the material is a good candidate for optoelectronic applications.

Porphyrins of systematically varying photoacoustic emission are designed by DFT and synthesized by controlling their molecular structures.