Synthesis and nonlinear optical properties of push-pull type stilbene and pyrazoline based chromophores

- Pairs of pyrazoline and stilbene derivatives have been analyzed.
- Horner-Wadsworth-Emmons (HWE) reaction was implemented.
- Second and third order of nonlinear optical properties were investigated.
- Dependence between chemical structure and NLO response was shown.

In this work we present the synthesis, spectroscopic and nonlinear optical properties of push-pull type organic dyes based on 1-phenyl-2-pyrazoline or 4-(dimethylamino)phenyl chromophores as a donor part, and bridged by a double bound ortho- or meta-substituted nitrophenyl group as an acceptor. For the optical measurements we have used the poly(methyl methacrylate) based thin films doped with the dyes. Third harmonic generation measurements were performed under the picosecond laser regime with excitation wavelength at 1064 nm. The experimental results confirmed that investigated systems can be used as the efficient nonlinear optical systems for harmonic of light generation (tripled but also doubled frequency). It has also been proved the strong dependence between chemical structure (position of electron-acceptor moiety as well as the type of electron-donor unit) and nonlinear optical (NLO) response coming from series of isomers and derivatives.

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