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Journal ArticleDOI

Nonresonant third order susceptibility measurements in a nematic liquid crystal‐PCH‐5

15 Aug 1992-Journal of Applied Physics (American Institute of Physics)-Vol. 72, Iss: 4, pp 1495-1497
TL;DR: In this paper, the real part of the third order nonlinear susceptibility χ(3) above the nematic to isotropic phase transition temperature of a nematic liquid crystal 4 (trans‐4'−4'n'n−pentylcyclohexy)‐benzonirtile (PCH‐5) from electro-optic Kerr effect experiments was determined.
Abstract: We report for the first time the determination of the real part of the third order nonlinear susceptibility χ(3)(−ω;ω,0,0) above the nematic to isotropic phase transition temperature of a nematic liquid crystal 4 (trans‐4’‐4’‐n‐pentylcyclohexy)‐benzonirtile (PCH‐5) from electro‐optic Kerr effect experiments. The value of χ(3) observed at 632.8 nm is found to be 6.2079×10−19 m2 V−2 close to the phase transition temperature at 55.1 °C.
Citations
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Journal ArticleDOI
Hari Singh Nalwa1
TL;DR: The current status of organic low-molecular weight and polymeric materials for third-order nonlinear optics is reviewed in this paper, where the importance of organic materials lies in their promise of large nonlinear optical figure of merit, high optical damage thresholds, ultrafast optical responses, architectural flexibility, and ease of fabrication.
Abstract: The current status of organic low-molecular weight and polymeric materials for third-order nonlinear optics is reviewed. The importance of organic materials lies in their promise of large nonlinear optical figure of merit, high optical damage thresholds, ultrafast optical responses, architectural flexibility, and ease of fabrication. Organic materials exhibiting interesting third-order nonlinear optical properties are discussed to illustrate the importance of structure–property correlations. Results on emerging organic materials that include liquids, dyes, fullerenes, charge-transfer complexes, π-conjugated polymers, dye-grafted polymers, organometallic compounds, composites, and liquid crystals are presented. Organic nonlinear optical materials seem promising for a wide range of applications and their potential for integrated optics should be further explored.

413 citations

Journal ArticleDOI
TL;DR: In this article, a new tolane-base liquid crystal, 4'-heptyl-3-fluoro-4-isothiocyanatotolane (7TOLF), and a biphenyl-base nematogen, 7BF, have been investigated for the first time to determine their electro-optical behavior and third order non-linearity using the static Kerr effect method.
Abstract: A new tolane-base liquid crystal, 4'-heptyl-3-fluoro-4-isothiocyanatotolane (7TOLF), and a biphenyl-base nematogen, 4'-heptyl-3-fluoro-4-isothiocyanatobiphenyl (7BF), have been investigated for the first time to determine their electro-optical behaviour and third order non-linearity using the static Kerr effect method. Both the nematic compounds have a fluorine atom attached to the phenyl-NCS moiety. They possess the same polar head group (-NCS) and alkyl tail (-C7H15). So the effect of the tolane group of nematogen on the electro-optical behaviour was investigated and compared. The temperature dependence of the electric Kerr constant in the isotropic phase and the pre-transitional behaviour has been investigated for these high birefringence compounds in the isotropic phase. Both the compounds have a positive and large Kerr constant which increases with decrease in temperature. The Landau–de Gennes model was obeyed for these compounds. For 7TOLF, the observed value of susceptibility, χ3 is about 228 times higher than that of CS2. The experimental Kerr effect data were also compared with those of the well-studied nematic liquid crystals.

25 citations

Journal ArticleDOI
TL;DR: The electrical and photoelectrical properties of aryl viologen (ArV), chemically known as 1,1′-diphenyl-4,4′-bipyridinium dichloride, in the form of thin film, sandwiched between ITO and In electrode were studied.

20 citations

Journal ArticleDOI
TL;DR: In this article, a large nonresonant third-order nonlinear susceptibility, X(3) (-ω; ω, 0, 0) was observed in the isotropic phase of a nematic liquid crystal 4′-n-hexyl-4-cyanobiphenyl (K18).
Abstract: We have observed a large nonresonant third-order nonlinear susceptibility, X(3) (-ω; ω, 0, 0) in the isotropic phase of a nematic liquid crystal 4′-n-hexyl-4-cyanobiphenyl (K18). The highest value of X(3) obtained at 632.8 nm is 1.16274×10-18 m2V-2 corresponding to a temperature 29.3°C. The observed second-order pretransitional temperature T* from our measurements is 1.2°C below the first-order nematic to isotropic transition temperature. The dependence of the Kerr constant on (T-T*)-1 is found to be in good agreement with the predictions of the Landau-de Gennes model.

4 citations

Journal ArticleDOI
TL;DR: In this paper, the real part of the third-order nonlinear susceptibility, x (3), was determined from electro-optic Kerr effect experiments in the isotropic phase of a nematic liquid crystal 4′-n-pentyl-4-cyanobiphenyl (K15).
Abstract: In this paper, we report for the first time the determination of the real part of the third-order nonlinear susceptibility, x (3)(−ω, ω, 0, 0), measurements in the isotropic phase of a nematic liquid crystal 4′-n-pentyl-4-cyanobiphenyl (K15) from electro-optic Kerr effect experiments. The value of x (3) obtained at 632·8 nm is found to be 1·08 × 10−18 m2 V−2 corresponding to a temperature 35·5°C and is the highest so far reported to the best of our knowledge.

2 citations

References
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Journal ArticleDOI
TL;DR: Four-wave mixing from composite artificial Kerr media consisting of ellipsoidal microparticles suspended in a host liquid is discussed and calculations of nonlinear grating formation and decay times are given in a dynamic model.
Abstract: Four-wave mixing from composite artificial Kerr media consisting of ellipsoidal microparticles suspended in a host liquid is discussed. Calculations of nonlinear grating formation and decay times are given in a dynamic model that includes the effect of random collisions on the particulates. Phase-conjugate efficiencies for a model configuration are given as well as operating limits imposed by particulate scattering from the composite.

24 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used degenerate four-wave mixing measurements in solution at 1.064 μm for partially doped states of the soluble, stable, reprocessible conducting polymers poly(4-amino biphenyl) [P(4ABP)] and poly(diphenyl amine) [DPA] whose synthesis and properties were reported earlier.
Abstract: Off‐resonant third‐order nonlinear optical susceptibilities using degenerate four‐wave mixing measurements in solution at 1.064 μm are reported for partially doped states of the soluble, stable, reprocessible conducting polymers poly(4‐amino biphenyl) [P(4ABP)] and poly(diphenyl amine) [P(DPA)] whose synthesis and properties were reported earlier. The polymers show appreciable nonlinearities, χ(3)xxxx being (1.4±0.3)×10−10 esu for P(4ABP) and (1.3±0.3)×10−10 esu for P(DPA), with a time response faster than 40 ps.

20 citations

Journal ArticleDOI
TL;DR: In this article, the phase conjugation in iodine-doped polyphenylacetylene is reported for the first time, and the third-order nonlinear optical susceptibility is measured in solutions of undoped and iodized polyphenylene by nanosecond degenerate four-wave mixing (DFWM).

16 citations

Journal ArticleDOI
TL;DR: In this article, the non-resonant part of the static non-linear susceptibility χ(3)1212 (ω 1,−ω1,o,o) in acetonitrile, benzaldehyde, acetophenone, acetone, ethyl methyl ketone, o-nitrotoluene, nitrobenzene, and benzoylchloride are reported.

15 citations

Journal ArticleDOI
TL;DR: In this paper, a tensor function describing the dependence of the dielectrical impermeability tensor on the electrical field tensor has been calculated for all 32 crystallographic classes.
Abstract: The sixth-rank tensor K describing the nonlinear electro-optical fourth-order effect has been calculated. A relationship between the non-zero components of the above tensor for all 32 crystallographic classes is shown. The calculations were executed with the aid of a tensor function describing the dependence of the dielectrical impermeability tensor on the electrical field tensor. It has been shown that changes in the optical properties of crystals due to the fourth-order electro-optical effect are similar to those brought about by the Kerr effect.

14 citations