The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Xinmu Zhang - One of the best experts on this subject based on the ideXlab platform.
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Strong terahertz magneto-Optical Phenomena based on quasi-bound states in the continuum and Fano resonances.
Optics express, 2019Co-Authors: Guo Chen, Weixuan Zhang, Xinmu ZhangAbstract:We propose new ways to produce strong terahertz (THz) magneto-Optical Phenomena from monolayer graphene based on bound states in the continuum (BICs) and Fano resonances. The BICs and Fano resonances of radiation modes in the monolayer graphene are realized by designing the photonic crystal slab-graphene-slab structure. Based on them, the magnetic circular dichroism near 100% has been achieved. Importantly, such magneto-Optical Phenomena can be modulated in intensity and frequency using only electrostatic doping at a fixed magnetic field. Comparing two ways to produce magneto-Optical Phenomena, it is found that the way based on BICs exhibits some advantages such as good electrical tenability due to narrower resonance width, higher conversion efficiency and more stability with the change of incident angle. These Phenomena can appear in a broad THz range by designing the nanostructures, which are very beneficial to polarization conversion and optoelectronic devices.
Marcos Tadeu T. Pacheco - One of the best experts on this subject based on the ideXlab platform.
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Analysis of the picosecond magneto-Optical Phenomena in scattering media of biological interest.
Physics in medicine and biology, 2002Co-Authors: Egberto Munin, Vicente Romeu Cianciarulo Longo, Antonio Balbin Villaverde, Marcos Tadeu T. PachecoAbstract:The behaviour of a magneto-Optically active biological-like medium under picosecond Optical excitation is analysed. The new technique is based on the fact that photons trapped in multiple scattering events inside the magneto-Optical medium leave the medium with larger induced rotation angles, as they travel longer distances. Two- and three-dimensional displacements of the photons in the medium are separately analysed. The dependence of this effect on the applied magnetic field strength, the value of the magneto-Optical constant of the medium and the standard deviation of the statistical distribution of the photons scattered inside the turbid medium are studied. The best values for the magnetic field and Optical parameters of the biological medium are proposed for the experimental observation of the picosecond magneto-Optical Phenomena in scattering media of biological origin. We also make some prospective studies to evaluate the potential application of the magneto-Optical effect as a tool for Optical tissue biopsy. Values for the optimum magnetic field intensities and for the expected experimental sensitivity in diverse conditions are reported.
Alexey B. Kuzmenko - One of the best experts on this subject based on the ideXlab platform.
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Electrically controlled terahertz magneto-Optical Phenomena in continuous and patterned graphene.
Nature communications, 2017Co-Authors: Jean-marie Poumirol, Peter Q. Liu, T. M. Slipchenko, Alexey Y. Nikitin, Luis Martín-moreno, Jérôme Faist, Alexey B. KuzmenkoAbstract:The magnetic circular dichroism and the Faraday rotation are the fundamental Phenomena of great practical importance arising from the breaking of the time reversal symmetry by a magnetic field. In most materials, the strength and the sign of these effects can be only controlled by the field value and its orientation. Furthermore, the terahertz range is lacking materials having the ability to affect the polarization state of the light in a non-reciprocal manner. Here we demonstrate, using broadband terahertz magneto-electro-Optical spectroscopy, that in graphene both the magnetic circular dichroism and the Faraday rotation can be modulated in intensity, tuned in frequency and, importantly, inverted using only electrostatic doping at a fixed magnetic field. In addition, we observe strong magneto-plasmonic resonances in a patterned array of graphene antidots, which potentially allows exploiting these magneto-Optical Phenomena in a broad THz range.
Vladimir M. Shalaev - One of the best experts on this subject based on the ideXlab platform.
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Surface-enhanced Optical Phenomena in nanostructured fractal materials
Handbook of Nanostructured Materials and Nanotechnology, 2000Co-Authors: Vladimir M. ShalaevAbstract:Publisher Summary This chapter considers surface-enhanced Optical Phenomena in objects with fractal morphology, such as aggregates of nanoparticles, self-affine surfaces, and random metaldielectric thin films. It is shown that Optical modes of such nanostructured random objects consist of localized sharp peaks resulting in very inhomogeneous spatial distributions of local fields. In peaks (hot spots), local fields exceed the applied field by several orders of magnitudes. These peaks are localized in nm-sized areas and they result from the excitation of the fractal plasmon modes. The strongly fluctuating fields associated with the sharp peaks in various random parts of a fractal lead to giant enhancements of Optical processes, especially, nonlinear ones that are proportional to the enhanced local field raised to a power higher than 1. The enhancement in these peaks is much larger (by several orders of magnitude) than the ensemble-average enhancement partially because the peaks are separated by distances much larger than the mode spatial sizes. Another important reason is related to the fact that the well-separated peaks represent often topologically disconnected parts of the same mode and therefore are correlated in phase. Destructive (in part) interference between the local field in different parts of a film results in the decreased average enhancements. It is shown experimentally that, in accordance with the theoretical predictions, the degree of localization of Optical excitations increases toward longer wavelengths.
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Nonlinear Optical Phenomena on rough surfaces of metal thin films
Physical Review B, 1998Co-Authors: Evgeni Poliakov, Vladimir M. Shalaev, Vadim A. Markel, Robert BotetAbstract:Nonlinear Optical Phenomena on rough self-affine metal surfaces are theoretically studied. Placing nonlinearly polarizable molecules on such surfaces results in strong enhancement of Optical nonlinearities. A quasistatic approximation is used to calculate local-enhancement factors for the second and third harmonic generation, degenerate four-wave mixing, and nonlinear Kerr effect. The calculations show that the average enhancement factors on a self-affine surface can be as large as ${10}^{7}$ and ${10}^{15}$ for Optical nonlinearities of the second and third order, respectively, with the maximum average enhancement in the infrared spectral range. Strong spatial inhomogeneity of local-enhancement distribution is demonstrated for the second and third harmonic generation. The local enhancement can exceed the average by several orders of magnitude, reaching extremely high values. Sharp peaks in local-field intensities at fundamental and generated frequencies are localized in spatially separated nanometer-sized areas of the film.
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Nonlinear Optical Phenomena in Nanostructured Fractal Materials
Journal of Nonlinear Optical Physics & Materials, 1998Co-Authors: Vladimir M. Shalaev, Vadim A. Markel, Evgeni Poliakov, Robert L. Armstrong, V. P. Safonov, Andrey K. SarychevAbstract:The results of theoretical and experimental studies of nonlinear Optical Phenomena in fractal nanostructures are reviewed. Localization of Optical excitations in fractal metal nanocomposites, such as colloidal aggregates, self-affine and semicontinuous films, results in strong enhancements of Optical nonlinearities. The localized modes of fractals cover a broad spectral range, from the visible to the far-infrared. A number of Optical processes are studied such as the Kerr-type nonlinearities, four-wave mixing, second and third harmonic generation and frequency- and polarization-selective photomodification.
B V Volovik - One of the best experts on this subject based on the ideXlab platform.
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Optical Phenomena connected with intraband carrier transitions in quantum dots and quantum wells
Nanotechnology, 2001Co-Authors: Leonid E. Vorobjev, S. N. Danilov, A V Gluhovskoy, V. L. Zerova, E.a. Zibik, V. Yu. Panevin, D. A. Firsov, Vadim Shalygin, A D Andreev, B V VolovikAbstract:Optical Phenomena in the mid-infrared range connected with interlevel and intersubband charge-carrier transitions in quantum dot and quantum well (QW) heterostructures under Optical and electrical pumping were investigated. Spectra of interband photoluminescence are also presented. The existence of a metastable level in funnel-shaped QWs is experimentally confirmed. The intersubband transition dynamics in asymmetrical pairs of tunnel-coupled QWs was studied by means of pump-and-probe time-resolved spectroscopy. This paper was presented at the 3rd Russian Workshop on Nanophotonics, Nizhnii Novgorod, Russia, 26-29 March 2001.
