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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
Feng Pan1, G. Knopfle1, Ch. Bosshard1, S. Follonier1, R. Spreiter1, Man Shing Wong1, Peter Günter1 
TL;DR: In this paper, the organic salt 4N,Ndimethylamino (DAST) was shown to be a very interesting material for electro-optic applications in the near infrared, and the electrooptic coefficients were determined in the spectral range of 700 up to 1535 nm using optical samples cut from large high quality bulk crystals.
Abstract: We show that the organic salt 4‐N,N‐dimethylamino‐4′‐N′‐methyl‐stilbazolium tosylate (DAST) is a very interesting material for electro‐optic applications in the near infrared. The electro‐optic coefficients, namely r111, r221, r331, r113, r223, and r333, were determined in the spectral range of 700 up to 1535 nm using optical samples cut from large high quality bulk crystals. DAST combines large electro‐optic coefficients, e.g., r111=77±8 pm/V at λ=800 nm and r111=47±8 pm/V at λ=1535 nm, with low dielectric constants, e.g., e1=5.2±0.4. This combination leads to large polarization‐optical coefficients.

348 citations

Journal ArticleDOI
TL;DR: In this article, the effective dielectric function for a medium of anisotropic inclusions embedded in an isotropic host is calculated using the Maxwell Garnett approximation for a model of quasi-one-dimensional organic polymers.
Abstract: The effective dielectric function ${\ensuremath{\epsilon}}_{e}$ for a medium of anisotropic inclusions embedded in an isotropic host is calculated using the Maxwell Garnett approximation. For uniaxial inclusions, ${\ensuremath{\epsilon}}_{e}$ depends on how well the inclusions are aligned. We apply this approximation to study ${\ensuremath{\epsilon}}_{e}$ for a model of quasi-one-dimensional organic polymers. The polymer is assumed to be made up of small single crystals embedded in an isotropic host of randomly oriented polymer chains. The host dielectric function is calculated using the effective-medium approximation (EMA). The resulting frequency-dependent ${\ensuremath{\epsilon}}_{e}(\ensuremath{\omega})$ closely resembles experiment. Specifically, $\mathrm{Re}{\ensuremath{\epsilon}}_{e}(\ensuremath{\omega})$ is negative over a wide frequency range, while $\mathrm{Im}{\ensuremath{\epsilon}}_{e}(\ensuremath{\omega})$ exhibits a broad ``surface plasmon'' band at low frequencies, which results from localized electronic excitations within the crystallites. If the host is above the conductivity percolation threshold, $\mathrm{Im}{\ensuremath{\epsilon}}_{e}(\ensuremath{\omega})$ has a low-frequency Drude peak in addition to the surface plasmon band, and $\mathrm{Re}{\ensuremath{\epsilon}}_{e}(\ensuremath{\omega})$ is negative over an even wider frequency range. We also calculate the cubic nonlinear susceptibility ${\ensuremath{\chi}}_{e}(\ensuremath{\omega})$ of the polymer, using a nonlinear EMA. At certain frequencies, ${\ensuremath{\chi}}_{e}(\ensuremath{\omega})$ is found to be strongly enhanced above that of the corresponding single crystals. Our results suggest that the electromagnetic properties of conducting polymers can be understood by viewing the material as randomly inhomogeneous on a small scale such that the quasistatic limit is applicable.

331 citations

Journal ArticleDOI
Hari Singh Nalwa1
TL;DR: In this article, the second and third-order NLO properties of organometallics have been reviewed, highlighting new materials that are emerging, which may have a wide range of applications in opto-electronics including integrated optics, optical switching, telecommunications, bistability and modulation.
Abstract: Almost three decades ago, the field of nonlinear optics evolved with the discovery of lasers. In the beginning, nonlinear optical (NLO) phenomena were investigated in inorganic materials, leading to the development of traditional NLO materials such as lithium niobate, potassium titanyl phosphate, quartz and gallium arsenide. In the 1970s, the importance of organic materials was realized because of the promise of large NLO responses, high laser damage thresholds, fast optical responses, architectural flexibility and ease of fabrication. Following work with organic materials, the scrutiny of organometallics also began recently. In organometallics, the metal-ligand bonding is expected to display large molecular hyperpolarizability because of the transfer of electron density between the metal atom and the conjugated ligand system. In organometallics, the diversity of central metals, oxidation states and ligands fosters in optimization of the charge-transfer interactions. Keeping this in view, second- and third-order NLO properties of organometallics have been reviewed here, highlighting new materials that are emerging. Organometallics may have a wide range of applications in opto-electronics including integrated optics, optical switching, telecommunications, bistability and modulation.

288 citations

Journal ArticleDOI
06 Dec 1991-Science
TL;DR: Second harmonic generation (SHG) shows that the multilayers have polar order that does not decrease with increasing numbers (up to a large number) of monolayers in the film.
Abstract: Polar orientation of molecules in solids leads to materials with potentially useful properties such as nonlinear optical and electrooptical activity, electrochromism, and pyroelectricity. A simple self-assembly procedure for preparing such materials is introduced that yields multiple polar dye monolayers on solid surfaces joined by zirconium phosphate-phosphonate interlayers. Second harmonic generation (SHG) shows that the multilayers have polar order that does not decrease with increasing numbers (up to a large number) of monolayers in the film. The inorganic interlayers, as determined by SHG, impart excellent orientational stability to the dye molecules, with the onset of orientational randomization above 150°C.

283 citations