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MonographDOI

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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Journal ArticleDOI
TL;DR: The first molecular hyperpolarizabilities (β) of a series of charge-transfer nonlinear optical (NLO) chromophores were measured with the hyper-Rayleigh scattering (HRS) technique using two excitation wavelengths at 1064 and 1907 nm as discussed by the authors.
Abstract: The first molecular hyperpolarizabilities (β) of a series of charge-transfer nonlinear optical (NLO) chromophores are measured with the hyper-Rayleigh scattering (HRS) technique using two excitation wavelengths at 1064 and 1907 nm The 1907 nm wavelength is the longest excitation wavelength used for the HRS experiment For some of these chromophores, β values in excess of 1000×10−30 esu at 1907 nm are obtained, and due to two-photon enhancement, even greater β values are found with the 1064 nm excitation Chromophores with such large hyperpolarizability are expected to have potential applications in practical electro-optical devices The dispersion of β is analyzed using a two-vibronic-state model developed previously in our laboratory The study shows that it is necessary to consider the vibronic structure of the chromophore in the excited state in order to account for the behavior of the first molecular hyperpolarizability of the charge-transfer NLO chromophores

27 citations

Journal ArticleDOI
TL;DR: In this paper, Pariser-Parr-Pople (PPP) calculations on long polyene and polydiacetylene oligomers containing up to 32 carbon atoms were performed at both Hartree-Fock and PPP configuration interaction with single excitations levels.
Abstract: We present Pariser–Parr–Pople (PPP) calculations on long polyene and polydiacetylene oligomers containing up to 32 carbon atoms. Working at both PPP restricted Hartree–Fock and PPP configuration interaction with single excitations levels, we study the excitation towards the 1 1B+u state. We report, as a function of chain length, the evolution of the transition energies and the modifications in geometry and atomic charges along the backbones. Comparison is made between the two series of oligomers. In the longer molecules, localization of the excitation is found, in agreement with the excitonic character of the transition to the 1 1B+u state.

27 citations

Journal ArticleDOI
TL;DR: The complex cubic susceptibility dispersion of side chain polymers containing 4−dialkylamino, 4'−nitro-stilbene, 4´alkoxy and 4´−4'−4`−4''nitro−stilbenes as their side groups has been measured in the range of 0953 μm to 1904 μm with third harmonic generation as mentioned in this paper.
Abstract: The complex cubic susceptibility dispersion of side chain polymers containing 4‐dialkylamino‐4’‐nitro‐stilbene, 4‐alkoxy‐4’‐nitro‐stilbene as their side groups has been measured in the range of 0953 μm to 1904 μm with third harmonic generation A two level model is compared to the experimental data in the three‐photon‐resonance spectral region Microscopic local field cascading was found to give an important contribution to the third order susceptibility Nonlinear susceptibilities comparable to those of fully conjugated backbone polymers are obtained

27 citations

Journal ArticleDOI
TL;DR: In this article, the authors measured the temperature and electric field dependence of the direct current (dc) electrical resistivity of several electro-optic polymers, in addition to pure polymethyl methacrylate (PMMA) and a commercial acrylate, UV‐15.
Abstract: We have measured the temperature and electric field dependence of the direct current (dc) electrical resistivity of several electro‐optic polymers, in addition to pure polymethyl methacrylate (PMMA) and a commercial acrylate, UV‐15. All the polymers exhibit a decrease in resistivity, to different degrees, with increasing temperature between room temperature and 130 °C. The results show that in a sandwich of multiple layers, the high temperature resistivity mismatch between individual layers results in field concentration in the layer with the highest electrical resistivity. This can be used to explain the enhanced electro‐optic coefficient measured in electro‐optic devices consisting of a sandwich of UV‐15/copolymer/UV‐15. In PMMA, we observed a saddle region in the temperature dependence of resistivity between 67 and 78 °C. Outside the saddle region, the resistivity of PMMA follows an Arrhenius relationship, with an activation energy of 1.0 eV. This saddle region is broadened in the nitro and DCV copolym...

27 citations

Journal ArticleDOI
TL;DR: In this article, a single crystal of l-asparagine monohydrate (LAM), organic nonlinear optical material has been grown by slow evaporation solution growth technique.
Abstract: Single crystal of l-asparagine monohydrate (LAM), organic nonlinear optical material has been grown by slow evaporation solution growth technique. Single crystal X-ray diffraction analysis was employed to identify the cell parameters. FT-IR analysis was used to estimate the qualitative presence of the amino acids in the grown crystal. Anisotropy properties like thermal and dielectric properties were studied on the grown crystal. The sample was thermally stable up to 125 °C. Also various thermodynamic properties were calculated and reported for the first time. Optical properties such as optical absorption, second harmonic generation, photoluminescence and photoconductivity analysis were also studied on the grown crystal. Optical absorption studies showed a lower UV cut-off of 225 nm. The SHG efficiency of the sample was seven times higher than that of KDP. Photoluminescence study confirms the suitability of the material for the generation of blue radiation. Multilayer plate-like pattern of growth was observed by scanning electron microscopy. The photoconductivity study confirms that the LAM crystal has negative photoconducting nature.

27 citations