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Ubiquity of optical activity in planar metamaterial scatterers  [PDF]
I. Sersic,M. A. van de Haar,F. Bernal Arango,A. F. Koenderink
Physics , 2012, DOI: 10.1103/PhysRevLett.108.223903
Abstract: Recently it was discovered that periodic lattices of metamaterial scatterers show optical activity, even if the scatterers or lattice show no 2D or 3D chirality, if the illumination breaks symmetry. In this Letter we demonstrate that such `pseudo-chirality' is intrinsic to any single planar metamaterial scatterer and in fact has a well-defined value at a universal bound. We argue that in any circuit model, a nonzero electric and magnetic polarizability derived from a single resonance automatically imply strong bianisotropy, i.e., magneto-electric cross polarizability at the universal bound set by energy conservation. We confirm our claim by extracting polarizability tensors and cross sections for handed excitation from transmission measurements on near-infrared split ring arrays, and electrodynamic simulations for diverse metamaterial scatterers.
Optical forces in nanorod metamaterial  [PDF]
Andrey A. Bogdanov,Alexander S. Shalin,Pavel Ginzburg
Physics , 2015,
Abstract: Optomechanical manipulation of micro and nano-scale objects with laser beams finds use in a large span of multidisciplinary applications. Auxiliary nanostructuring could substantially improve performances of classical optical tweezers by means of spatial localization of objects and intensity required for trapping. Here we investigate a three-dimensional nanorod metamaterial platform, serving as an auxiliary tool for the optical manipulation, able to support and control near-field interactions and generate both steep and flat optical potential profiles. It was shown that the 'topological transition' from the elliptic to hyperbolic dispersion regime of the metamaterial, usually having a significant impact on various light-matter interaction processes, does not strongly affect the distribution of optical forces in the metamaterial. This effect is explained by the predominant near-fields contributions of the nanostructure to optomechanical interactions. Semi-analytical model, approximating the finite size nanoparticle by a point dipole and neglecting the mutual re-scattering between the particle and nanorod array, was found to be in a good agreement with full-wave numerical simulation. In-plane (perpendicular to the rods) trapping regime, saddle equilibrium points and optical puling forces (directed to the excitation light source along the rods), acting on a particle situated inside or at the nearby the metamaterial, were found. The auxiliary metamaterials, employed for optical manipulation, provide additional degrees of freedom in flexible nano-mechanical control and could be employed in various cross-disciplinary applications.
Anisotropic Metamaterial Optical Fibers  [PDF]
Dheeraj Pratap,S. Anantha Ramakrishna,Justin G. Pollock,Ashwin K. Iyer
Physics , 2014, DOI: 10.1364/OE.23.009074
Abstract: Internal physical structure can drastically modify the properties of waveguides: photonic crystal fibers are able to confine light inside a hollow air core by Bragg scattering from a periodic array of holes, while metamaterial loaded waveguides for microwaves can support propagation at frequencies well below cutoff. Anisotropic metamaterials assembled into cylindrically symmetric geometries constitute light-guiding structures that support new kinds of exotic modes. A microtube of anodized nanoporous alumina, with nanopores radially emanating from the inner wall to the outer surface, is a manifestation of such an anisotropic metamaterial optical fiber. The nanopores, when filled with a plasmonic metal such as silver or gold, greatly increase the electromagnetic anisotropy. The modal solutions in anisotropic circular waveguides can be uncommon Bessel functions with imaginary orders.
Magneto-optical spaser  [PDF]
D. G. Baranov,A. P. Vinogradov,A. A. Lisyansky,Yakov M. Strelniker,David J. Bergman
Physics , 2012,
Abstract: We present an electrodynamical model of a novel quantum plasmonic device - magneto-optical spaser. It is shown that a spherical gain nanoparticle coated with a metallic magneto-optical shell can operate as a spaser amplifying circularly polarized surface plasmons. The magneto-optical spaser may be used in design of optical isolator in plasmonic transmission lines as well as in spaser spectrometry of chiral molecules.
On Negative Index Metamaterial Spacers and Their Unusual Optical Properties
Muhammad I. Aslam;Durdu Oe Gueney
PIER B , 2013, DOI: 10.2528/PIERB12111908
Abstract: We theoretically investigate the possibility of using a metamaterial structure as a spacer, named as metaspacer, which can be integrated with other materials in microfabrication. We show that such metaspacers can provide new optical behaviors that are not possible through conventional spacers. In particular, we investigate negative index metaspacers embedded in fishnet metamaterial structures and compare them with conventional fishnet metamaterial structures. We show that the negative index metaspacer based fishnet structure exhibits intriguing inverted optical response. We also observe that the dependence of the resonance frequency on the geometric parameters is reversed. We conclude with practicality of these metaspacers.
On Negative Index Metamaterial Spacers and Their Unusual Optical Properties  [PDF]
Muhammad I. Aslam,Durdu ?. Güney
Physics , 2012,
Abstract: We theoretically investigate the possibility of using a metamaterial structure as a spacer, named as metaspacer, which can be integrated with other materials in microfabrication. We show that such metaspacers can provide new optical behaviors that are not possible through conventional spacers. In particular, we investigate negative index metaspacers embedded in fishnet metamaterial structures and compare them with conventional fishnet metamaterial structures. We show that the negative index metaspacer based fishnet structure exhibits intriguing inverted optical response. We also observe that the dependence of the resonance frequency on the geometric parameters is reversed. We conclude with practicality of these metaspacers.
Magneto-Optical Modulation Ellipsometry  [PDF]
Otar Bakradze*,Zurab Alimbarashvili,Rusiko Janelidze
Physics , 2009,
Abstract: The paper investigates the ellipsometric method of measuring the magneto-optical parameter and optical constants in one experiment at affixed angle of the light incidence in ferromagnetics. The influence of the magnetization modulation on the change of ellipsometrical angles is shown. The method is considered for the geometries of polar, meridional and equatorial reflection Kerr effects. The formulae relating to the measured signals in polarizer-subject-analyzer (PSA) circuit with four magneto-optical and optical constants illustrated by the example of ferromagnetic Ni are given.
Magneto optical trapping of Barium  [PDF]
S. De,U. Dammalapati,K. Jungmann,L. Willmann
Physics , 2008, DOI: 10.1103/PhysRevA.79.041402
Abstract: First laser cooling and trapping of the heavy alkaline earth element barium has been achieved based on the strong 6s$^2$ $^1$S$_0$ - 6s6p $^1$P$_1$ transition for the main cooling. Due to the large branching into metastable D-states several additional laser driven transitions are required to provide a closed cooling cycle. A total efficiency of $0.4(1) \cdot 10^{-2}$ for slowing a thermal atomic beam and capturing atoms into a magneto optical trap was obtained. Trapping lifetimes of more than 1.5 s were observed. This lifetime is shortened at high laser intensities by photo ionization losses. The developed techniques will allow to extend significantly the number of elements that can be optically cooled and trapped.
Resonant nonlinear magneto-optical effects in atoms  [PDF]
D. Budker,W. Gawlik,D. F. Kimball,S. M. Rochester,V. V. Yashchuk,A. Weis
Physics , 2002, DOI: 10.1103/RevModPhys.74.1153
Abstract: In this article, we review the history, current status, physical mechanisms, experimental methods, and applications of nonlinear magneto-optical effects in atomic vapors. We begin by describing the pioneering work of Macaluso and Corbino over a century ago on linear magneto-optical effects (in which the properties of the medium do not depend on the light power) in the vicinity of atomic resonances, and contrast these effects with various nonlinear magneto-optical phenomena that have been studied both theoretically and experimentally since the late 1960s. In recent years, the field of nonlinear magneto-optics has experienced a revival of interest that has led to a number of developments, including the observation of ultra-narrow (1-Hz) magneto-optical resonances, applications in sensitive magnetometry, nonlinear magneto-optical tomography, and the possibility of a search for parity- and time-reversal-invariance violation in atoms.
Exchanging Ohmic Losses in Metamaterial Absorbers with Useful Optical Absorption for Photovoltaics  [PDF]
Ankit Vora,Jephias Gwamuri,Nezih Pala,Anand Kulkarni,Joshua M. Pearce,Durdu ?. Güney
Physics , 2014,
Abstract: Using metamaterial absorbers, we have shown that metallic layers in the absorbers do not necessarily constitute undesired resistive heating problem for photovoltaics. Tailoring the geometric skin depth of metals and employing the natural bulk absorbance characteristics of the semiconductors in those absorbers can enable the exchange of undesired resistive losses with the useful optical absorbance in the active semiconductors. Thus, Ohmic loss dominated metamaterial absorbers can be converted into photovoltaic near-perfect absorbers with the advantage of harvesting the full potential of light management offered by the metamaterial absorbers. Based on experimental permittivity data for indium gallium nitride, we have shown that between 75%-95% absorbance can be achieved in the semiconductor layers of the converted metamaterial absorbers. Besides other metamaterial and plasmonic devices, our results may also apply to photodectors and other metal or semiconductor based optical devices where resistive losses and power consumption are important pertaining to the device performance.
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