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, it was shown that linearity and planarity are two dominating factors in the second-order cubic hyperpolarizability of polyaromatic rings, and the planarity defined mathematically can be served as a scale of conjugation in p-conjugation systems.
Abstract: The semiempirical AM1-calculated cubic hyperpolarizability is found to Ž be surprisingly low in C , which is in agreement with recent experimental results. In 60 the past, 10 orders of magnitude discrepancy has existed in the literature for the cubic . hyperpolarizabilities of C . Comparing some selected groups of polyaromatic 60 hydrocarbons, we show that linearity and planarity are two dominating factors in the second hyperpolarizability in polyaromatic rings. Therefore, the observations that aromatic rings on C lose their linearity and planarity account for the low second 60 hyperpolarizability. Furthermore, the planarity defined mathematically can be served as a scale of conjugation in p-conjugation systems. By using biphenyl as a reference, the cubic hyperpolarizability of C can be estimated by the scaling of conjugation. Q 1999 60 John Wiley & Sons, Inc. Int J Quant Chem 75: 457]463, 1999
1 citations
01 Jan 1989
TL;DR: In this article, a requirement for the application of the Langmuir-Blodgett technique is the incorporation of an hydrophobic moiety to render the molecules amphiphilic.
Abstract: Organic molecules with large second-order polarizabilities offer an important potential for applications requiring nonlinear optical properties, e.g. optical signal processing (1,2). Unfortunately most molecules crystallize in centrosymmetric structures preventing their use for quadratic nonlinear optics. The Langmuir-Blodgett technique (3), which allows the fabrication of thin films from these molecules in a non-centrosymmetric lattice, offers good possibilities to circumvent this restriction (4–8). A requirement for the application of the LB-technique is the incorporation of an hydrophobic moiety to render the molecules amphiphilic.
1 citations
Journal Article•
TL;DR: In this paper, a novel organic nonlinear optical material 4-chloro -N- methyl 4-stilbazolium tosylate was synthesized and good optical quality single crystals of size 10 mm x 6 mm x 2 mm were grown by slow evaporation technique.
Abstract: A novel organic non-linear optical material 4-chloro -N- methyl 4-stilbazolium tosylate, a new derivative of the stilbazolium tosylate family has been synthesized and good optical quality single crystals of size 10 mm x 6 mm x 2 mm were grown by slow evaporation technique. The grown crystals were subjected to different instrumentation methods for characterization. The diffraction planes were identified and indexed by powder X-ray diffraction analysis. The crystal system and lattice parameters were found from single crystal X-ray diffraction. Fourier transform infrared was recorded to confirm the functional groups. In order to study the optical quality of the grown crystal, the UV-VIS spectrum was recorded in the solution state and cut off wavelength was determined. Vickers Microhardness test was carried out and Meyer’s index ‘n’ was calculated. Being nonlinear optical material, second harmonic efficiency was determined in comparison with urea.
1 citations
01 Jan 2002
TL;DR: In this paper, the change in NLO properties associated with photochromism of the previously mentioned photochromes, the photoassisted poling of spiropyrans and fulgides in polymethylmethacrylate (PMMA) films and the photoswitching of the second-order NLO property of PMMA films doped with different photo-chromes (spiropyan, fulgide, and dithienylethenes) and also of anil crystals.
Abstract: Spiropyrans, spirooxazins, fulgides, and dithienylethenes give rise to thermally metastable or stable photoisomers when imbedded in polymer films. Furthermore, the NLO properties drastically change when going from the colorless to the colored isomer of these photochromes. In this chapter, we will present the change in NLO properties associated with photochromism of the previously mentionned photochromes, the photoassisted poling of spiropyrans and fulgides in polymethylmethacrylate (PMMA) films and the photoswitching of the second-order NLO properties of PMMA films doped with different photochromes (spiropyrans, fulgides, and dithienylethenes) and also of anil crystals. Potential applications of these phenomena in optical signal processing and optical data storage will be described.
1 citations
TL;DR: It is confirmed that £20,000 will be spent on reparations for damage caused by the earthquake in Nepal.
Abstract: 我々は, 非常に高い確率で非中心対称構造を構築できる分子設計法 (Λ形分子) を見いだし, かつこの手法はバルク位相整合に最適な材料設計になることを明らかにした。種々の置換基の導入やメチレン基以外の結合などにより, Λ形分子の誘導体は無数に考えられ, またこのことは異方性や屈折率の制御にもつながる可能性があり, 新材料を探索するうえで非常に役立つと思われる。有機低分子材料は, 国内外で精力的に研究されてはいるものの, デバイス化のための結晶育成法や材料複合化技術などは試行錯誤しながら進められているのが現状である。材料開発者がデバイス研究者と協力して, 有機材料の特徴を生かし, 取扱いの難しさなどの欠点を克服しながら実用化を目指した研究をすることが必要である。
1 citations