The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Tobin J Marks - One of the best experts on this subject based on the ideXlab platform.
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third and fifth order nonlinear Optical response of a tict stilbene hybrid chromophore
Journal of Physical Chemistry C, 2020Co-Authors: Sepehr Benis, Alexander Baev, Eric W Van Stryland, David J Hagan, Tobin J MarksAbstract:Twisted intramolecular charge transfer (TICT) chromophores exhibit a promising third-order nonlinear Optical (NLO) response, γ, which is potentially useful for all-Optical switching. Here we explore the third- and fifth-order NLO response of a newly synthesized chromophore, TMC-3′, which incorporates both stilbene and TICT motifs with Optical Function. Solution Z-scan measurements in CH2Cl2 reveal modest two-photon absorptions (2PA) at 1100 and 800 nm (σ2PA > 80 GM), and two contributions to the nonlinear refraction. The first component is attributed to the third-order bound-electronic response, while the second is assigned to a fifth-order process involving 2PA induced excited state refraction (2PA-ESR). Quantum computation suggests that the differences between the present work and previous studies lie primarily in the addition of the stilbene related states, as well as the increase in ground state dipole moment. This work yields insight into the third- and fifth-order NLO response of TICT chromophores a...
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third and fifth order nonlinear Optical response of a tict stilbene hybrid chromophore
The Journal of Physical Chemistry, 2020Co-Authors: Alexander J T Lou, Sepehr Benis, Alexander Baev, David J Hagan, Munan Gao, David Kim, Eric W Van Stryland, Tobin J MarksAbstract:Twisted intramolecular charge transfer (TICT) chromophores exhibit a promising third-order nonlinear Optical (NLO) response, γ, which is potentially useful for all-Optical switching. Here we explore the third- and fifth-order NLO response of a newly synthesized chromophore, TMC-3′, which incorporates both stilbene and TICT motifs with Optical Function. Solution Z-scan measurements in CH₂Cl₂ reveal modest two-photon absorptions (2PA) at 1100 and 800 nm (σ₂PA > 80 GM), and two contributions to the nonlinear refraction. The first component is attributed to the third-order bound-electronic response, while the second is assigned to a fifth-order process involving 2PA induced excited state refraction (2PA-ESR). Quantum computation suggests that the differences between the present work and previous studies lie primarily in the addition of the stilbene related states, as well as the increase in ground state dipole moment. This work yields insight into the third- and fifth-order NLO response of TICT chromophores and demonstrates that subtle structural modifications significantly impact their Functionality.
Richard O Prum - One of the best experts on this subject based on the ideXlab platform.
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structure and Optical Function of amorphous photonic nanostructures from avian feather barbs a comparative small angle x ray scattering saxs analysis of 230 bird species
Journal of the Royal Society Interface, 2012Co-Authors: Vinodkumar Saranathan, Jason D Forster, Heeso Noh, Sengfatt Liew, S G J Mochrie, Hui Cao, Eric R Dufresne, Richard O PrumAbstract:Non-iridescent structural colours of feathers are a diverse and an important part of the phenotype of many birds. These colours are generally produced by three-dimensional, amorphous (or quasi-ordered) spongy b-keratin and air nanostructures found in the medullary cells of feather barbs. Two main classes of three-dimensional barb nanostructures are known, characterized by a tortuous network of air channels or a close packing of spheroidal air cavities. Using synchrotron small angle X-ray scattering (SAXS) and Optical spectrophotometry, we characterized the nanostructure and Optical Function of 297 distinctly coloured feathers from 230 species belonging to 163 genera in 51 avian families. The SAXS data provided quantitative diagnoses of the channel- and sphere-type nanostructures, and confirmed the presence of a predominant, isotropic length scale of variation in refractive index that produces strong reinforcement of a narrow band of scattered wavelengths. The SAXS structural data identified a new class of rudimentary or weakly nanostructured feathers responsible for slate-grey, and blue-grey structural colours. SAXS structural data provided good predictions of the singlescattering peak of the Optical reflectance of the feathers. The SAXS structural measurements of channel- and sphere-type nanostructures are also similar to experimental scattering data from synthetic soft matter systems that self-assemble by phase separation. These results further support the hypothesis that colour-producing protein and air nanostructures in feather barbs are probably self-assembled by arrested phase separation of polymerizing b-keratin from the cytoplasm of medullary cells. Such avian amorphous photonic nanostructures with isotropic Optical properties may provide biomimetic inspiration for photonic technology.
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structure Function and self assembly of single network gyroid i4132 photonic crystals in butterfly wing scales
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Vinodkumar Saranathan, S G J Mochrie, Eric R Dufresne, Chinedum O Osuji, Suresh Narayanan, Alec Sandy, Richard O PrumAbstract:Complex three-dimensional biophotonic nanostructures produce the vivid structural colors of many butterfly wing scales, but their exact nanoscale organization is uncertain. We used small angle X-ray scattering (SAXS) on single scales to characterize the 3D photonic nanostructures of five butterfly species from two families (Papilionidae, Lycaenidae). We identify these chitin and air nanostructures as single network gyroid (I4132) photonic crystals. We describe their Optical Function from SAXS data and photonic band-gap modeling. Butterflies apparently grow these gyroid nanostructures by exploiting the self-organizing physical dynamics of biological lipid-bilayer membranes. These butterfly photonic nanostructures initially develop within scale cells as a core-shell double gyroid (Ia3d), as seen in block-copolymer systems, with a pentacontinuous volume comprised of extracellular space, cell plasma membrane, cellular cytoplasm, smooth endoplasmic reticulum (SER) membrane, and intra-SER lumen. This double gyroid nanostructure is subsequently transformed into a single gyroid network through the deposition of chitin in the extracellular space and the degeneration of the rest of the cell. The butterflies develop the thermodynamically favored double gyroid precursors as a route to the Optically more efficient single gyroid nanostructures. Current approaches to photonic crystal engineering also aim to produce single gyroid motifs. The biologically derived photonic nanostructures characterized here may offer a convenient template for producing Optical devices based on biomimicry or direct dielectric infiltration.
Toru Noda - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Optical Function using a new point spread Function analysis system in cataractous and pseudophakic eyes: preliminary results.
Japanese journal of ophthalmology, 2006Co-Authors: Kazuno Negishi, K. Kobayashi, Kazuhiko Ohnuma, Kenji Ohno, Toru NodaAbstract:Purpose To evaluate Optical Function in cataractous and pseudophakic eyes using the new point spread Function (PSF) analysis system in a clinical setting.
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Evaluation of Optical Function Using a New Point Spread Function Analysis System in Cataractous and Pseudophakic Eyes: Preliminary Results
Japanese Journal of Ophthalmology, 2006Co-Authors: Kazuno Negishi, K. Kobayashi, Kazuhiko Ohnuma, Kenji Ohno, Toru NodaAbstract:Purpose To evaluate Optical Function in cataractous and pseudophakic eyes using the new point spread Function (PSF) analysis system in a clinical setting. Methods We applied this new analysis system in the study of two cataractous eyes and one pseudophakic eye of two patients. Using a PSF analyzer, double-pass PSF was measured directly for each subject, and the single-pass modulation transfer Function (MTF) and single-pass PSF were calculated. The simulated retinal images of various sizes of Landolt's rings and their contrast characteristics were also calculated by the PSF analyzer. Results The MTF and the contrast of the simulated retinal images degraded in cataractous eyes were compared with data for normal eyes; the degradation pattern depended on the opacification pattern. The MTF and the contrast of the simulated retinal images in the pseudophakic eye improved significantly compared with the cataractous eyes, although both values were lower in the pseudophakic eye than in young normal eyes. Conclusions Our data showed degradation of Optical Function in cataractous and pseudophakic eyes in comparison with Optical Function in young normal eyes. If further accumulations of PSF data are made, it may be possible to establish an objective standard by which to measure the progression of cataract, as well as an objective indication for treatment in the future. Jpn J Ophthalmol 2006;50:12–19 © Japanese Ophthalmological Society 2006
Andrei Faraon - One of the best experts on this subject based on the ideXlab platform.
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Decoupling Optical Function and geometrical form using conformal flexible dielectric metasurfaces
Nature Communications, 2016Co-Authors: Seyedeh Mahsa Kamali, Yu Horie, Amir Arbabi, Ehsan Arbabi, Andrei FaraonAbstract:Physical geometry and Optical properties of objects are correlated: cylinders focus light to a line, spheres to a point, and arbitrarily shaped objects introduce Optical aberrations. Multi-Functional components with decoupled geometrical form and Optical Function are needed when specific Optical Functionalities must be provided while the shapes are dictated by other considerations like ergonomics, aerodynamics, or esthetics. Here we demonstrate an approach for decoupling Optical properties of objects from their physical shape using thin and flexible dielectric metasurfaces which conform to objects' surface and change their Optical properties. The conformal metasurfaces are composed of silicon nano-posts embedded in a polymer substrate that locally modify near-infrared ($\it{\lambda}$ = 915 nm) Optical wavefronts. As proof of concept, we show that cylindrical lenses covered with metasurfaces can be transformed to Function as aspherical lenses focusing light to a point. The conformal metasurface concept is highly versatile for developing arbitrarily shaped multi-Functional Optical devices.
Vinodkumar Saranathan - One of the best experts on this subject based on the ideXlab platform.
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structure and Optical Function of amorphous photonic nanostructures from avian feather barbs a comparative small angle x ray scattering saxs analysis of 230 bird species
Journal of the Royal Society Interface, 2012Co-Authors: Vinodkumar Saranathan, Jason D Forster, Heeso Noh, Sengfatt Liew, S G J Mochrie, Hui Cao, Eric R Dufresne, Richard O PrumAbstract:Non-iridescent structural colours of feathers are a diverse and an important part of the phenotype of many birds. These colours are generally produced by three-dimensional, amorphous (or quasi-ordered) spongy b-keratin and air nanostructures found in the medullary cells of feather barbs. Two main classes of three-dimensional barb nanostructures are known, characterized by a tortuous network of air channels or a close packing of spheroidal air cavities. Using synchrotron small angle X-ray scattering (SAXS) and Optical spectrophotometry, we characterized the nanostructure and Optical Function of 297 distinctly coloured feathers from 230 species belonging to 163 genera in 51 avian families. The SAXS data provided quantitative diagnoses of the channel- and sphere-type nanostructures, and confirmed the presence of a predominant, isotropic length scale of variation in refractive index that produces strong reinforcement of a narrow band of scattered wavelengths. The SAXS structural data identified a new class of rudimentary or weakly nanostructured feathers responsible for slate-grey, and blue-grey structural colours. SAXS structural data provided good predictions of the singlescattering peak of the Optical reflectance of the feathers. The SAXS structural measurements of channel- and sphere-type nanostructures are also similar to experimental scattering data from synthetic soft matter systems that self-assemble by phase separation. These results further support the hypothesis that colour-producing protein and air nanostructures in feather barbs are probably self-assembled by arrested phase separation of polymerizing b-keratin from the cytoplasm of medullary cells. Such avian amorphous photonic nanostructures with isotropic Optical properties may provide biomimetic inspiration for photonic technology.
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structure Function and self assembly of single network gyroid i4132 photonic crystals in butterfly wing scales
Proceedings of the National Academy of Sciences of the United States of America, 2010Co-Authors: Vinodkumar Saranathan, S G J Mochrie, Eric R Dufresne, Chinedum O Osuji, Suresh Narayanan, Alec Sandy, Richard O PrumAbstract:Complex three-dimensional biophotonic nanostructures produce the vivid structural colors of many butterfly wing scales, but their exact nanoscale organization is uncertain. We used small angle X-ray scattering (SAXS) on single scales to characterize the 3D photonic nanostructures of five butterfly species from two families (Papilionidae, Lycaenidae). We identify these chitin and air nanostructures as single network gyroid (I4132) photonic crystals. We describe their Optical Function from SAXS data and photonic band-gap modeling. Butterflies apparently grow these gyroid nanostructures by exploiting the self-organizing physical dynamics of biological lipid-bilayer membranes. These butterfly photonic nanostructures initially develop within scale cells as a core-shell double gyroid (Ia3d), as seen in block-copolymer systems, with a pentacontinuous volume comprised of extracellular space, cell plasma membrane, cellular cytoplasm, smooth endoplasmic reticulum (SER) membrane, and intra-SER lumen. This double gyroid nanostructure is subsequently transformed into a single gyroid network through the deposition of chitin in the extracellular space and the degeneration of the rest of the cell. The butterflies develop the thermodynamically favored double gyroid precursors as a route to the Optically more efficient single gyroid nanostructures. Current approaches to photonic crystal engineering also aim to produce single gyroid motifs. The biologically derived photonic nanostructures characterized here may offer a convenient template for producing Optical devices based on biomimicry or direct dielectric infiltration.