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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."
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Show moreTime-resolved single photon counting is used for measuring Kleinman-disallowed nonlinear tensor components in order to evaluate molecular materials for chiral axial organic nonlinear optical materials. The experimental setup and results are described. © 2004 Optical Society of America.
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Show moreWe have investigated the formation of in-bandgap delocalized modes due to random lattice disorder as determined from the longitudinal mode spacing in a distributed Bragg laser. We were able to measure the penetration depth, and from transfer matrix simulations, determine how the localization length is altered for disordered lattices. Transfer matrix simulations and studies of the ensemble average were able to connect the gap delocalized modes to localized modes outside of the gap as expected from consideration of Anderson localization, as well as identify the controlling parameters. © 2009 Optical Society of America. This paper was published in Optics Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-17-20-18038. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.
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Show moreA tunable source is used to study the competition between hyper-Rayleigh scattering (HRS) and multi-photon fluorescence in the detected signal near the second-harmonic by examining the spectral content of the scattered light and its dispersion in the infrared. It is found that even at frequencies noticeably lower than half that of the linear absorption, there is a rapid decrease in the HRS peak and rapid increase in two photon fluorescence. This is attributed to dephasing of the virtual excited state. This transition occurs far from the resonance peak. Two compounds, p-nitroaniline and disperse red 1, are studied, showing that accurate internal referencing can be carried out by considering the symmetry of the solvent to yield accurate measurements of the first hyperpolarizability.
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