All-Optical Poling and Two-Photon Absorption in Heterocyclic Azo Dyes with Different Side Groups

Abstract

We investigated the optical properties of heterocyclic azo dyes with different side groups prepared: as powders, in PMMA matrix, and side-chain polymers. We characterized the nonlinear optical effects of these compounds by Z-scan and all-optical poling techniques and supported these experiments with theoretical modeling. It was found that these materials show strong two-photon absorption cross sections exceeding 20 GM, which is 1 order of magnitude stronger than that of similar materials (azobenzene and p-amino­azobenzene). Our study reveals the dominant role of the side-chain system over the guest–host one and stresses the importance of the substituent in the efficiency of the poling process.

Two-photon absorption and two-photon-induced isomerization of azobenzene compounds

“…Substitution of AB with EDG/EWG groups enhanced NLO properties and this effect is more pronounced when both donor and acceptor substituents are present (push-pull system). 70,72,74 To fully characterize the inuence of substituent on NLO properties of AB derivatives Kamounah et al synthesized azobenzenes modied with groups of different strength of the donor and/or acceptor. 69 It is known that the TPA cross-section for organic molecules depends on the intramolecular chargetransfer (ICT) efficiency in push/pull type structures (D/A-p-D/A) as well as the length of the p-conjugation.…”

Physico-Chemical and Light-Induced Properties of Quinoline Azo-dyes Polymers

“…General procedure for synthesis of 5-azo-8-hydroxyquinoline dyes is known [11,12,20,31]. Aromatic amine (a-g) (35 mmol) was dissolved in concentrated HCl (30 mL).…”

“…Proper modification of the properties of molecules can be achieved by extending the conjugation length of the π-electron system or molecular planarity strengthening. In case of azobenzene, it is common practice to introduce the electron donating/withdrawing groups into the phenyl rings (D-π-A systems), which make them intramolecular charge transfer (ITC) chromophores [10][11][12][13]. Another way of tuning their properties is changing the different moieties in the phenyl rings, which are attached to the azo bridge [12,13].…”

Changes in Optical Properties of Azopolymers in an Electric Field

“…Polymers containing chromophore molecules have been extensively studied by many research groups due to their promising photonic applications to the optical data storage, surface-relief holography, optical switching, etc. [1][2][3][4][5][6][7][8]. The desirable properties of azobenzene materials are attributed to the highly efficient photo-reversable trans-cis isomerization of azobenzene moieties [9][10][11].…”