- Light scattering (x)
- Search results
Search results
Show moreQuadrupolar and octupolar invariants may be used as methods to attain noncentrosymmetric materials for application in second order nonlinear optics. The structure-property relationships for the J = 2, or quadrupole rotational invariant, are investigated. Proper citation for the Technical Digest CD-ROM should be written in the following format: Ostrovekhov V., Ostroverkhova O., Petschek R.G., Singer K.D., Sukhomlinova L., Twieg R.J., “`Quadrupolar' molecular nonlinear optics,” in the Conference on Lasers and Electro-Optics (CLEO)/The International Quantum Electronics Conference (IQEC) (Optical Society of America, Washington, DC, 2009), Proceedings, 8-9
Show less
Show moreKerr measurements, ellipsometry, and quasielastic light scattering have been used to probe nematic fluctuations and nematic wetting at an isotropic liquid crystal-substrate interface in four generations of liquid crystalline monodendrons and dendrimers. We find that the pretransitional behavior is qualitatively similar to that of low molecular weight liquid crystals, exhibiting a Landau-like divergence of the relaxation time and a logarithmic divergence of the optical retardation on approaching the nematic-isotropic phase transition from above. Quantitatively, we find that the transition temperatures of the monodendrons are typically about 0.5 K above the supercooling limit of the isotropic phase and that the orientational viscosities may be fit to a power law in molecular weight Mn, where the exponent ≤ 1.0. Appropriate credit for the requested material should be given as follows: "Reprinted (adapted) with permission from Macromolecules 29:24, 7813-7819. Copyright 1996 American Chemical Society."
Show less
Show moreThe spectral content of hyper-Rayleigh scattering (HRS) was studied with solutions of disperse red-1 (DR1) in acetone at a specific fundamental wavelength. Dephasing can occur when the effective lifetime of the virtual state approaches a two-photon resonance. Experiments were developed that will measure all six observables in HRS by observing the scattering at 45°, continuously varying the phase of the fundamental by rotating a quarter-waveplate, and using another quarter-waveplate with a linear polarizer to analyze the harmonic. These experiments proved the validity of Kleinmann symmetry in near-resonant and far off-resonant regimes. In any electronic posting permitted by this Section 8.1.9, the following copyright notice must be displayed on the initial screen displaying IEEE-copyrighted material: "©1997 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works."
Show less
Show moreA dc electric field was applied perpendicular to the tilt plane of a pitch-compensated (unwound helix) anticlinic liquid crystal. By means of quasielastic light scattering, the field was found to couple the acoustic and optic Goldstone modes, resulting in an increase of the relaxation time τβ of the acoustic like eigenmode. Elastic constants were estimated from the relaxation time data. ©2000 The American Physical Society. Appropriate bibliographic citation and notice of the APS copyright must be included- "Zhang S., Keast S.S., Neubert M.E., Petschek R.G., Rosenblatt C., Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics 62:5 B, R5911-R5914 (2000). Copyright 2000 by the American Physical Society."
Show less
Show moreAn investigation on light scattering above the nematic - smectic-A phase transition in binary mixtures of bent-core mesogens and calamitic was performed. With dopant concentration X, the regular part of the bend elastic constant decreased strongly. It was found that the divergent part of the bend elastic constant decreased rapidly with X, when close to the nematic - smectic-A phase transition temperature. Appropriate bibliographic citation and notice of the APS copyright must be included- "Dodge M.R., Petschek R.G., Rosenblatt C., Neubert M.E., Walsh M.E., Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 68:3 1, 317031-317036, 2003. Copyright 2003 by the American Physical Society."
Show less