Nonlinear optical properties of organic and polymeric materials
29 Sep 1983-
About: The article was published on 1983-09-29 and is currently open access. It has received 762 citations till now.
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TL;DR: In this article, a microscopic many-electron description for the third order de-induced second harmonic susceptibility γ ijkl (-2ωω,ω,0) of all trans-polyenes is reported.
Abstract: A microscopic many-electron description is reported for the third order de-induced second harmonic susceptibility γ ijkl (-2ωω,ω,0) of all trans-polyenes. Based on results obtained by self consistent field configuration interaction theory that suitably accounts for electron-electron interactions and by direct comparison with experimental gas phase results, we show that symmetry-controlled electron correlation effects determine the properties and behavior of γ ijkl (-2ωω,ω,0) for polyene chains of length 4 through 16 carbon sites. Under well-defined symmetry conditions, the many-electron mechanism involves third order virtual excitations to high-lying, strongly electron correlated two-photon 1 A g states. The major component γ xxxx (-2ωω,ω,0) with all fields aligned along the chain axis exhibits a power law dependence of 5.4 due to three major factors which are described.
9 citations
TL;DR: In this paper, 1,5-Diphenylpenta-2,4-dien-1-one (DDO) chalcone single crystals, synthesized by a base-catalysed aldol condensation reaction between cinnamaldehyde and acetophenone, have been grown by the slow evaporation of an ethanol solution.
Abstract: 1,5-Diphenylpenta-2,4-dien-1-one (DDO) chalcone single crystals, synthesized by a base-catalysed aldol condensation reaction between cinnamaldehyde and acetophenone, have been grown by the slow evaporation of an ethanol solution. The crystals belong to the orthorhombic system with centrosymmetric space group Pbca. The DDO crystals are transparent in the visible region and have a lower optical cut-off at ∼445 nm with a band-gap energy of 2.87 eV. Thermogravimetry/differential scanning calorimetry thermal analysis shows that the crystal is stable up to 375 K and it has a good chemical stability. The vibrational patterns of the chalcone have been investigated by Fourier transform IR and Fourier transform Raman spectroscopy. Microhardness studies were also carried out to elucidate the mechanical behaviour. Theoretical calculations were performed using the Hartree–Fock method with 6-31G(d,p) as the basis set, and the first-order hyperpolarizability is 7.077 × 10−30 electrostatic units, which is >25 times that of urea. The crystalline perfection evaluated by high-resolution X-ray diffraction analysis reveals multiple peaks. The molecular packing leads to a centrosymmetric arrangement, resulting in zero second harmonic generation [χ(2) = 0] efficiency. Interestingly, the bromo- and chloro-substituted chalcones are good nonlinear optical materials.
9 citations
Cites background from "Nonlinear optical properties of org..."
...Another importance of this type of compound is its high photosensitivity and thermal stability, which are used in developing various crystalline electro-optical devices (Williams, 1983)....
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TL;DR: In this article, the authors measured third-order nonlinear susceptibilities χ(3) for a variety of polysilanes with different side-groups, and for composites of polysanes and metals.
Abstract: We have measured third-order nonlinear susceptibilities χ(3) for a variety of polysilanes with different side-groups, and for composites of polysilanes and metals. The value of χ(3) varies substantially with changes in the side-groups, backbone conformation, film thickness, orientation, and volume fraction and size of metal particles. We have also prepared thin films of high optical quality, which have been used to study material properties and material response for waveguiding studies.
9 citations
TL;DR: In this paper, the structure-polarization relationship has been investigated in a series of polyenes and various conjugation patterns have been studied and their effect on the polarizability and hyperpolarizabilities has been commented upon.
Abstract: The structure-polarization relationship has been investigated in a series of polyenes. Various conjugation patterns have been studied and their effect on the␣polarizabilities and hyperpolarizabilities has been commented upon. Two classes of conjugated oligomers have been shown to have very large second hyperpolarizabilities. It is shown that the known potential of the conjugated chains to lead to large nonlinearities is enhanced by substituting one or more hydrogen atoms with lithium. This interesting and useful point is documented by calculating the hyperpolarizabilities of several selected organolithium derivatives presenting a variety of molecular structures. The largest computed nonlinearity is γ = 4 × 107 a.u., which is an exceptionally large value. The present computations have been performed using the semi-empirical approaches MNDO, PM3 and MNDO/d. This choice of well-tested semi-empirical models, in connection with the available literature values (theoretical and experimental), supports the validity of the reported findings.
9 citations
TL;DR: In this article, normal incidence transmission measurements and surface plasmonspectroscopy at optical frequencies are used to probe the optical and structural properties of an optically nonlinear dye, deposited onto glass and silver substrates by the Langmuir-Blodgett technique.
Abstract: Normal incidence transmission measurements and surface plasmonspectroscopy at optical frequencies are used to probe the optical and structural properties of an optically nonlinear dye, deposited onto glass and silver substrates by the Langmuir–Blodgett technique. The particular orientation and proximity to the silversurface afforded by the deposition method reveals strong molecule/metal interactions hitherto unreported for LB film assemblies on silver.
9 citations