Search results for "Nonlinear optic"
showing 10 items of 530 documents
Synthesis, crystal structures, and solid state quadratic nonlinear optical properties of a series of stilbazolium cations combined with gold cyanide …
2011
Three salts built up from (E)-4′-(dimethylamino)-stilbazolium (DMAS)H+, (E)-4′-(diethylamino)-stilbazolium (DEAS)H+, (E)-4′-{2-(methoxymethyl) pyrrolidinyl}-stilbazolium (MPS)H+, and gold cyanide as a counter-ion, are reported. The crystal structures have been solved for (DEAS)H+ Au(CN)2− (Cc space group), and for (MPS)H+ Au(CN)2− (P1 space group). The semi-empirical (ZINDO) calculated static hyperpolarizability (β0) of (MPS)H+ is equal to 147 × 10−30 cm5esu−1, in solid state, which is 25% higher than that of the cation of the well known (E)-4′-(dimethylamino)-methylstilbazolium tosylate (DAST). (MPS)H+ Au(CN)2− exhibits a unique crystal structure in which the cations are perfectly aligned.…
Conjugated Oligomers with Terminal Donor–Acceptor Substitution
2005
Conjugated oligomers represent a prominent class of compounds from a viewpoint of their theory, synthesis, and applications in materials science. Push-pull substitution with an electron donor D at one end of the conjugation and an electron acceptor A at the other end results in them having outstanding optical and electronical properties. This Review highlights fundamental synthetic strategies for the preparation of such oligomers with n repeat units (n=1, 2, 3, 4, ..) and the rules that govern their linear and nonlinear optical properties (absorption, frequency doubling and tripling). The unification of chemical, physical, and theoretical aspects with an interdisciplinary image of this clas…
Theoretical characterization of the electronic structure of polymeric systems combining disilanylene and /spl pi/-conjugated units
1994
Summary form only given. Polymeric organosilicon systems are in the forefront of research, due to their intriguing properties (semiconducting behavior, photoconduction, non-linear optical properties, and thermo- and piezochromism). The fundamental skeletons of most of these polymers consist of a /spl sigma/-electron network formed by silicon-silicon bonds. Recently, polymeric organosilicon systems containing a regular alternation of a disilanylene unit and carbon /spl pi/-conjugated moiety as phenylene, ethynylene, or ethenylene have been synthesized. The purpose of this contribution is to perform a detailed study of the electronic structure of polymers containing alternated disilanylene an…
Stability of the functional NLO polymers–optically induced depoling of the DMABI molecules in sPMMA matrix
2008
Abstract Low polar order (PO) stability is the major problem of the polymer materials for nonlinear optical (NLO) applications. In this contribution we will show the results of PO stability investigations in the corona poled 3 wt.% DMABI + sPMMA guest–host system. Influence of the poling temperature on the building and stability of the polar order in the system will be presented. To characterize the stability, PO destruction has been caused by high intensity light. Polar order stability characteristics were obtained from the sample second harmonic generation intensity (SHI) time decays. We have found that the decay signal is the best fit to the sum of two exponentials. Several physical mode…
<title>All-optical poling of DMABI molecules in a polymer matrix</title>
2005
Many organic compounds in solid state have nonlinear optical properties due to the orientation of the molecules in a polymer matrix. In this work, all-optical poling and second harmonic generation in a composition consisting of 1 mass% of N,N-dimethylaminobenzylidene 1,3-indandione (DMABI) compound in poly(methyl methacrylate) (PMMA) matrix were studied. Thin films were prepared by solvent casting. The 1.064-μm fundamental and 532-nm second harmonic wavelengths of a Nd:YAG laser were used. It is shown that DMABI molecules can be oriented by the method of all- optical poling, and that the process is related to the photoinduced switching between two equally stable states of the molecule.
Second-order NLO main-chain polymers by polymerization of poled monomers
1993
A new method of preparing oriented NLO main chain polymers is presented. We synthesized NLO-monomers that consist of donor acceptor substituted tolane molecules that can be poled in the low molar mass state. In the oriented polar state these monomers can be chemically linked using a thermally activated polyaddition reaction. This reaction links the donor head of one monomer to the acceptor tail of the next hibiting bulk noncentrosymmetry with the average direction of the molecular dipoles parallel to the aligning field.
<title>Nonlinear optical properties of some indandione-1,3 pyridinium betaine derivatives</title>
1997
In this paper nonlinear optical properties of indandione-1,3 pyridinium betaine (IPB) molecule and its novel amphiphilic derivatives have been studied. Hyper-Rayleigh scattering (HRS) has been used as a direct and accurate tool to determine effective hyperpolarizability (beta) of IPB derivatives dissolved in chloroform. Evaluation of hyperpolarizability gives an averaged values of (beta) from 140 multiplied by 10-30 to 450 multiplied by 10-30 esu. Disordering of molecular orientation for multilayer Langmuir-Blodgett films of compound C17-IPB has been studied by SHG techniques and discussed for different film thickness. It has been observed that orientation degree of the Z-type molecular str…
ChemInform Abstract: Preparation and Nonlinear Optics of Monodisperse Oligo(1,4-phenyleneethynylene)s.
2010
Oligo(1,4-phenyleneethynylene)s 1a−e, with solubilizing propoxy side chains, were prepared by use of Hagihara−Sonogashira coupling reactions. The synthetic strategy was based on a building block system and on the use of trimethylsilyl and triisopropylsilyl protecting groups that could be cleaved selectively. The extension of the conjugation with an increasing number of repeat units provokes a bathochromic shift of the long wavelength absorption and a superlinear increase of the second hyperpolarizability |γ|. The corresponding third harmonic generation (THG) measurements were performed using polystyrene matrices and variable laser wavelengths. We conclude that the conjugation length is much…
An improved molecular design of obtaining NLO active molecular glasses using triphenyl moieties as amorphous phase formation enhancers
2012
New molecular design of obtaining molecular glasses has been developed by linking triphenylmethyl moieties to chromophore core by flexible C-C bridge. Compounds capable of forming stable amorphous phase with good optical quality have been acquired with increased chemical and thermal sustainability compared to the previously reported design. NLO activity of compounds has been measured after corona discharge polling. Compared to previously synthesized trityloxy fragment containing compounds increase of d 33 coefficient by up to 17 times was achieved for the same chromophore core containing compounds.
Macrocycles as Molecular Units to Build up Electroresponsive Materials: A Comparative Theoretical Investigation of the Electronic and Optical Propert…
1990
Besides their classical and well-known applications as, e.g., dyes, pigments, catalysts, etc. [1], phthalocyanines (Pc’s) have been of particular interest in many fields of basic and applied research concerning solar cells [2], photosensitizers [3], low dimensional metals [4], gas sensors [5], electrochromism [6], Langmuir-Blodgett (LB) films [7], and nonlinear optics [8]. As an example, gas sensors [9], electronic devices [10], laser recording materials [11], and photovoltaic cells [12] can now be built from LB films of phthalocyanines. This great variety of interesting applications results from a number of unique properties that phthalocyanines exhibit On the one hand, they show an except…