Synthesis and optical properties of polyacetylenes containing nonlinear optical chromophores

Nonlinear optical properties DFT calculations of polyacethylene and copolymers models substituted with aldimines chromophores as side chains

Aldimine derivatives chromophores grafted on polyacetylene oligomers were first designed to investigate the nonlinear optical (NLO) response of the resulting materials using CAMB3LYP method. The effects of different factors such as the chain length separating the substitutions as well as the configurations and the orientations of these latter, were examined and discussed. In a second part of this paper, NLO responses, in particular the static hyperpolarizabilities of polyvinyl oligomers substituted by aldimine chromophores via carboxylic groups and by pyrrolidone groups were calculated for different configurations. The stability and the hydrogen bonding in each oligomer were also discussed.

Quadratic Non-Linear Optical Properties of the poly(2,5-bis(but-2-ynyloxy) Benzoate Containing the 2-(ethyl(4-((4-nitrophenyl)buta-1,3-diynyl)phenyl)amino)ethanol) Chromophore

Excellent quadratic non-linear optical (ONL-2) properties of the poly(2,5-bis(but-2-ynyloxy) benzoate, containing a polar diacetylene as a chromophore, were found. According with the Maker fringes method, oriented polymer films showing an order parameter of ∼0.23 can display outstanding and stable Second Harmonic Generation (SHG) effects under off-resonant conditions (SHG-532 nm). Also, the macroscopic non-linear optical (NLO)-coefficients were evaluated under the rod-like molecular approximation, obtaining: χ_zzz⁽²⁾ and χ_zxx⁽²⁾ in the order of 280 ± 10 and 100 ± 10 pm V^-1, respectively. The mechanical and chemical properties, in addition to the large ONL-2 coefficients exhibited by this polymer, make it a promising organic material in the development of optoelectronic/photonic devices.

Nonlinear Optical Materials for the Smart Filtering of Optical Radiation

The control of luminous radiation has extremely important implications for modern and future technologies as well as in medicine. In this Review, we detail chemical structures and their relevant photophysical features for various groups of materials, including organic dyes such as metalloporphyrins and metallophthalocyanines (and derivatives), other common organic materials, mixed metal complexes and clusters, fullerenes, dendrimeric nanocomposites, polymeric materials (organic and/or inorganic), inorganic semiconductors, and other nanoscopic materials, utilized or potentially useful for the realization of devices able to filter in a smart way an external radiation. The concept of smart is referred to the characteristic of those materials that are capable to filter the radiation in a dynamic way without the need of an ancillary system for the activation of the required transmission change. In particular, this Review gives emphasis to the nonlinear optical properties of photoactive materials for the function of optical power limiting. All known mechanisms of optical limiting have been analyzed and discussed for the different types of materials.

Studies of third-order optical nonlinearities and optical limiting of 2, 3-butanedione dihydrazone

2, 3-butanedione dihydrazone (BDDH) synthesized via chemical route and nonlinear optical parameters, such as nonlinear refractive index (n2), nonlinear absorption coefficient (β), third-order nonlinear optical susceptibility (χ(3)), second hyperpolarizability (γ), and optical-limiting behavior were investigated by single beam z-scan technique for different concentrations. Synthesized sample were irradiated by a Q-switched, frequency doubled Nd:YAG laser and found that n2 and β increases linearly with increasing concentration and hence γ decreases linearly. The excited-state absorption cross sections of BDDH were found to be larger than ground-state absorption cross sections, and it leads to reverse saturable absorption (RSA). The experimental results are well in agreement with the theory and also establish BDDH as one of the potential candidate materials for optical limiting at 532 nm.