Synthesis and nonlinear optical properties in the near-IR range of stilbazolium dyes

A series of stilbazolium salts with A-π-A model and their third-order nonlinear optical response in the near-IR region

A series of water-soluble stilbazolium salts with A-π-A (A: Acceptor) model have been synthesized and fully characterized. The results obtained from absorption spectra and TD-DFT computational studies show that there is a relative strong intramolecular charge transfer (ICT) transition from pyridine unit to pyridine cation of the stilbazolium salts. Furthermore, it is found that the three stilbazolium salts (T1, T2, T3) show the strong two-photon absorption (2PA) response in the near-infrared (IR) region by Z-scan technique using femtosecond laser. And the stilbazolium salt T3 shows the largest two-photon absorption cross-section and third-order nonlinear optical (NLO) coefficient χ⁽³⁾ at 730nm, indicating the different terminal substituent group of the pyridinium plays a vital role in third-order NLO behavior.

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.

Optical spectroscopic studies on the complexation of stilbazolium dyes with a water soluble pillar[5]arene

The host–guest interactions of carboxylato-pillar[5]arene (WPA5) and three stilbazolium dyes were studied by optical spectroscopy. A fluorescence indicator displacement based on WPA5 was shown to detect paraquat in aqueous solution.