The Experts below are selected from a list of 2592 Experts worldwide ranked by ideXlab platform
Rajadurai Chandrasekar - One of the best experts on this subject based on the ideXlab platform.
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chiral Organic Photonics self assembled micro resonators for an enhanced circular dichroism effect in the non linear optical signal
Journal of Materials Chemistry C, 2017Co-Authors: Dasari Venkatakrishnarao, Chakradhar Sahoo, E A Mamonov, V B Novikov, N V Mitetelo, Sri Ram G Naraharisetty, T V Murzina, Rajadurai ChandrasekarAbstract:Chiro-optical signals from chiral molecules/structures are inherently weak. In particular, enhancing the circular-dichroism (CD) effect (different absorption of left or right circularly polarized light) in the non-linear optical (NLO) signal from chiral molecular materials is challenging and imperative since it is advantageous in various areas, from biomedical sciences to miniaturized photonic devices. Here we suggest and realize for the first time an approach to enhance the CD effect taking advantage of the NLO effects resonantly enhanced in the nonlinear chiral Organic micro-resonators. These R- and S-type resonators in the form of micro-spheres are prepared by the self-assembly technique from the corresponding axially chiral enantiomeric molecules, namely R- and S-4-[2,2′-diethoxy-6′-(4-formylphenyl)-[1,1′-binaphthalen]-6-yl]benzaldehyde in CHCl3/MeOH mixtures. Each enantiomeric micro-sphere, upon optical pumping, acts as a whispering gallery mode (WGM) resonator as the photo-luminescence (PL) is excited in a single- or in a two-photon regime. We show that the NLO-CD effect and the two-photon absorption (TPA) in the case of micro-spheres are at least twice as high as compared to a continuous film of the same effective thickness. This is due to pronounced field localization effects in micro-spheres with high Q-factor, which increases the photon residence time (τP) in a chiral medium and thus strengthens the light–matter interaction. Finite-difference time-domain (FDTD) numerical calculations confirm a strong light localization near the boundary of the micro-spheres.
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Organic Photonics: prospective nano/micro scale passive Organic optical waveguides obtained from π-conjugated ligand molecules.
Physical chemistry chemical physics : PCCP, 2014Co-Authors: Rajadurai ChandrasekarAbstract:Nano/micro scale passive Organic optical waveguides, which are self-assembled from tailor made Organic molecules, are one of the less studied branches of Organic Photonics. This perspective article is primarily focused on the research work related to one dimensional (1D) passive Organic optical waveguides. In the beginning, a brief theory of Organic waveguides, recent works on active Organic waveguides and attempts towards fabrication of integrated photonic components and circuits will be discussed. Later more focus will be given to passive Organic wave guiding materials derived from 1D hexagonal submicrotubes, parallelepipedic nanotubes, shape shifting Organic structures and paramagnetic tubes. By using laser ablation techniques, the polishing of Organic tube tips, the precise control of the light propagation distance and the creation of multiple optical outputs will be discussed. This perspective also highlights some noteworthy applications of passive Organic waveguides in remote sensing, excitation and defect identification. The end of this article concludes with the potential of passive Organic optical waveguides in future Organic nanoPhotonics.
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Organic Photonics prospective nano micro scale passive Organic optical waveguides obtained from π conjugated ligand molecules
Physical Chemistry Chemical Physics, 2014Co-Authors: Rajadurai ChandrasekarAbstract:Nano/micro scale passive Organic optical waveguides, which are self-assembled from tailor made Organic molecules, are one of the less studied branches of Organic Photonics. This perspective article is primarily focused on the research work related to one dimensional (1D) passive Organic optical waveguides. In the beginning, a brief theory of Organic waveguides, recent works on active Organic waveguides and attempts towards fabrication of integrated photonic components and circuits will be discussed. Later more focus will be given to passive Organic wave guiding materials derived from 1D hexagonal submicrotubes, parallelepipedic nanotubes, shape shifting Organic structures and paramagnetic tubes. By using laser ablation techniques, the polishing of Organic tube tips, the precise control of the light propagation distance and the creation of multiple optical outputs will be discussed. This perspective also highlights some noteworthy applications of passive Organic waveguides in remote sensing, excitation and defect identification. The end of this article concludes with the potential of passive Organic optical waveguides in future Organic nanoPhotonics.
Wolfgang Freude - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear silicon Photonics
Nature Photonics, 2010Co-Authors: Juerg Leuthold, Christian Koos, Wolfgang FreudeAbstract:The increasing capability for manufacturing a wide variety of optoelectronic devices from polymer and polymer–silicon hybrids, including transmission fibre, modulators, detectors and light sources, suggests that Organic Photonics has a promising future in communications and other applications. The nonlinearities in silicon are diverse. This Review covers the wealth of nonlinear effects in silicon and highlights the important applications and technological solutions in nonlinear silicon Photonics.
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Highly nonlinear silicon Photonics slot waveguides without free carrier absorption related speed-limitations
2008 34th European Conference on Optical Communication, 2008Co-Authors: Thomas Vallaitis, Christian Koos, Bweh Esembeson, Ivan Biaggio, Tsuyoshi Michinobu, François Diederich, Pieter Dumon, Roeland Baets, Wolfgang Freude, Juerg LeutholdAbstract:Nonlinear losses of highly nonlinear silicon/Organic Photonics slot waveguides are analyzed. Unlike silicon strip waveguides, slot waveguides do not show absorption related speed limitations up to highest input powers.
Michael R. Wasielewski - One of the best experts on this subject based on the ideXlab platform.
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cyanated perylene 3 4 dicarboximides and perylene 3 4 9 10 bis dicarboximide facile chromophoric oxidants for Organic Photonics and electronics
Chemistry of Materials, 2003Co-Authors: Michael J. Ahrens, Michael J. Fuller, Michael R. WasielewskiAbstract:Cyanated perylene-3,4-dicarboximides and perylene-3,4:9,10-bis(dicarboximide)s absorb strongly in the visible spectrum and are strong oxidants. The stable radical anions of these molecules form reversibly and are also chromophores. These molecules significantly expand the library of perylene derivatives that can be employed as charge generators and carriers in molecular Photonics and electronics applications, such as n-type Organic semiconductors.
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Aminated and Cyanated Perylene Mono- and Diimides: Liquid Crystalline Electron Donors and Acceptors for Organic Photonics and Electronics
Frontiers in Optics, 2003Co-Authors: Michael J. Ahrens, Michael J. Fuller, Michael R. WasielewskiAbstract:The development of Organic Photonics and electronics has fueled the need for stable chromophores that can undergo photoinduced electron transfer reactions to yield stable radical ion intermediates. Derivatives of perylene-3,4:9,10-bis(dicarboximide) (PDI) and perylene-3,4-dicarboximide (PMI) are especially intriguing because they show exceptional chemical and photochemical stability. These molecules and their derivatives have been used as building blocks for molecular switches, wires, and logic gates, as well as Organic light-emitting diodes, light-harvesting arrays, photorefractive thin films, and solar cells. Much of this work has benefited greatly from the distinct electronic absorption spectra that the radical ions of these molecules exhibit, and their ability to self-assemble into extended structures. The former makes it possible to easily identify these radical ion intermediates in complex electron transfer reactions, while the latter offers the possibility of self-assembling photofunctional materials. The photophysical and redox properties of these molecules can be manipulated by functionalizing the perylene core with electron donating and accepting functional groups. For example, substitution of the 1,7-positions of PDI, or the 9-position of PMI with N-cycloalkylamines, such as N-pyrrolidine, produces chromophores in which the lowest energy electronic transition acquires significant charge transfer character and moves to substantially longer wavelengths relative to those of PMI or PDI. Moreover, the one-electron oxidation potentials become significantly less positive, making these derivatives excellent electron donors in donor-acceptor materials. Substitution of the corresponding positions with cyano groups leads to the cyanated chromophores CN2PDI, CNPMI, and CN3PMI. These molecules are powerful, yet stable, photochemical oxidants for use in novel photonic and electronic materials. Liquid crystalline derivatives of 1,7-cyano and 1,7-bis(N-pyrrolidinyl)PDI self-assemble into ordered structures.
Juerg Leuthold - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear silicon Photonics
Nature Photonics, 2010Co-Authors: Juerg Leuthold, Christian Koos, Wolfgang FreudeAbstract:The increasing capability for manufacturing a wide variety of optoelectronic devices from polymer and polymer–silicon hybrids, including transmission fibre, modulators, detectors and light sources, suggests that Organic Photonics has a promising future in communications and other applications. The nonlinearities in silicon are diverse. This Review covers the wealth of nonlinear effects in silicon and highlights the important applications and technological solutions in nonlinear silicon Photonics.
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Highly nonlinear silicon Photonics slot waveguides without free carrier absorption related speed-limitations
2008 34th European Conference on Optical Communication, 2008Co-Authors: Thomas Vallaitis, Christian Koos, Bweh Esembeson, Ivan Biaggio, Tsuyoshi Michinobu, François Diederich, Pieter Dumon, Roeland Baets, Wolfgang Freude, Juerg LeutholdAbstract:Nonlinear losses of highly nonlinear silicon/Organic Photonics slot waveguides are analyzed. Unlike silicon strip waveguides, slot waveguides do not show absorption related speed limitations up to highest input powers.
Michael J. Ahrens - One of the best experts on this subject based on the ideXlab platform.
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cyanated perylene 3 4 dicarboximides and perylene 3 4 9 10 bis dicarboximide facile chromophoric oxidants for Organic Photonics and electronics
Chemistry of Materials, 2003Co-Authors: Michael J. Ahrens, Michael J. Fuller, Michael R. WasielewskiAbstract:Cyanated perylene-3,4-dicarboximides and perylene-3,4:9,10-bis(dicarboximide)s absorb strongly in the visible spectrum and are strong oxidants. The stable radical anions of these molecules form reversibly and are also chromophores. These molecules significantly expand the library of perylene derivatives that can be employed as charge generators and carriers in molecular Photonics and electronics applications, such as n-type Organic semiconductors.
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Aminated and Cyanated Perylene Mono- and Diimides: Liquid Crystalline Electron Donors and Acceptors for Organic Photonics and Electronics
Frontiers in Optics, 2003Co-Authors: Michael J. Ahrens, Michael J. Fuller, Michael R. WasielewskiAbstract:The development of Organic Photonics and electronics has fueled the need for stable chromophores that can undergo photoinduced electron transfer reactions to yield stable radical ion intermediates. Derivatives of perylene-3,4:9,10-bis(dicarboximide) (PDI) and perylene-3,4-dicarboximide (PMI) are especially intriguing because they show exceptional chemical and photochemical stability. These molecules and their derivatives have been used as building blocks for molecular switches, wires, and logic gates, as well as Organic light-emitting diodes, light-harvesting arrays, photorefractive thin films, and solar cells. Much of this work has benefited greatly from the distinct electronic absorption spectra that the radical ions of these molecules exhibit, and their ability to self-assemble into extended structures. The former makes it possible to easily identify these radical ion intermediates in complex electron transfer reactions, while the latter offers the possibility of self-assembling photofunctional materials. The photophysical and redox properties of these molecules can be manipulated by functionalizing the perylene core with electron donating and accepting functional groups. For example, substitution of the 1,7-positions of PDI, or the 9-position of PMI with N-cycloalkylamines, such as N-pyrrolidine, produces chromophores in which the lowest energy electronic transition acquires significant charge transfer character and moves to substantially longer wavelengths relative to those of PMI or PDI. Moreover, the one-electron oxidation potentials become significantly less positive, making these derivatives excellent electron donors in donor-acceptor materials. Substitution of the corresponding positions with cyano groups leads to the cyanated chromophores CN2PDI, CNPMI, and CN3PMI. These molecules are powerful, yet stable, photochemical oxidants for use in novel photonic and electronic materials. Liquid crystalline derivatives of 1,7-cyano and 1,7-bis(N-pyrrolidinyl)PDI self-assemble into ordered structures.