Showing papers by "Yuri S. Kivshar published in 2010"
TL;DR: In this paper, the authors introduce the concept of Fano resonances, which can be reduced to the interaction of a discrete (localized) state with a continuum of propagation modes, and explain their geometrical and/or dynamical origin.
Abstract: Modern nanotechnology allows one to scale down various important devices (sensors, chips, fibers, etc.) and thus opens up new horizons for their applications. The efficiency of most of them is based on fundamental physical phenomena, such as transport of wave excitations and resonances. Short propagation distances make phase-coherent processes of waves important. Often the scattering of waves involves propagation along different paths and, as a consequence, results in interference phenomena, where constructive interference corresponds to resonant enhancement and destructive interference to resonant suppression of the transmission. Recently, a variety of experimental and theoretical work has revealed such patterns in different physical settings. The purpose of this review is to relate resonant scattering to Fano resonances, known from atomic physics. One of the main features of the Fano resonance is its asymmetric line profile. The asymmetry originates from a close coexistence of resonant transmission and resonant reflection and can be reduced to the interaction of a discrete (localized) state with a continuum of propagation modes. The basic concepts of Fano resonances are introduced, their geometrical and/or dynamical origin are explained, and theoretical and experimental studies of light propagation in photonic devices, charge transport through quantum dots, plasmon scattering in Josephson-junction networks, and matter-wave scattering in ultracold atom systems, among others are reviewed.
2,520 citations
TL;DR: This work demonstrates a new principle of optical trapping and manipulation increasing more than 1000 times the manipulation distance by harnessing strong thermal forces while suppressing their stochastic nature with optical vortex beams.
Abstract: We demonstrate a new principle of optical trapping and manipulation increasing more than 1000 times the manipulation distance by harnessing strong thermal forces while suppressing their stochastic nature with optical vortex beams. Our approach expands optical manipulation of particles into a gas media and provides a full control over trapped particles, including the optical transport and pinpoint positioning of $\ensuremath{\sim}100\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ objects over a meter-scale distance with $\ifmmode\pm\else\textpm\fi{}10\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ accuracy.
265 citations
TL;DR: In this paper, the effect of time reversals and nonlinear wave dynamics in a symmetric optical coupler with balanced gain and loss was shown to be a general connection between time reversal and wave dynamics, and it was shown that for intensities below a threshold level, the amplitudes oscillate between the waveguides.
Abstract: We reveal a generic connection between the effect of time reversals and nonlinear wave dynamics in systems with parity-time ($\mathcal{PT}$) symmetry, considering a symmetric optical coupler with balanced gain and loss where these effects can be directly observed experimentally. We show that for intensities below a threshold level, the amplitudes oscillate between the waveguides, and the effects of gain and loss are exactly compensated after each period due to periodic time reversals. For intensities above a threshold level, nonlinearity suppresses periodic time reversals, leading to the symmetry breaking and a sharp beam switching to the waveguide with gain. Another nontrivial consequence of linear $\mathcal{PT}$ symmetry is that the threshold intensity remains the same when the input intensities at waveguides with loss and gain are exchanged.
219 citations
TL;DR: It is demonstrated analytically and by first-principles electromagnetic simulations that, by breaking the time-reversal symmetry, nonreciprocal spoof surface plasmons enable a dramatic optical response: one-way extraordinary optical transmission.
Abstract: We introduce a concept of a nonreciprocal spoof surface plasmon: an electromagnetic wave supported by a structured conductor embedded in an asymmetric magneto-optical medium and exhibiting a nonreciprocal dispersion It is demonstrated analytically and by first-principles electromagnetic simulations that, by breaking the time-reversal symmetry, nonreciprocal spoof surface plasmons enable a dramatic optical response: one-way extraordinary optical transmission
192 citations
TL;DR: In this article, the authors demonstrate that edge roughness can suppress thermal conductivity by two orders of magnitude, and that this effect is associated with the edge-induced energy localization and suppression of the phonon transport.
Abstract: We analyze numerically thermal conductivity of graphene nanoribbons with perfect and rough edges. We demonstrate that edge roughness can suppress thermal conductivity by two orders of magnitude. This effect is associated with the edge-induced energy localization and suppression of the phonon transport, and it becomes more pronounced for longer nanoribbons and low temperatures.
166 citations
TL;DR: In this article, the near-field interaction between the resonant subwavelength elements of a metamaterial was analyzed and a method to calculate the electric and magnetic interaction coefficients was presented.
Abstract: We analyze the near-field interaction between the resonant subwavelength elements of a metamaterial and present a method to calculate the electric and magnetic interaction coefficients. We show that by adjusting the relative configuration of the neighboring split ring resonators it becomes possible to manipulate this near-field interaction, and thus tune the response of metamaterials. We use the results of this analysis to explain the experimentally observed tuning of microwave metamaterials.
137 citations
TL;DR: It is demonstrated that such nonlinear binary lattices support stable discrete solitons, which can be adiabatically tuned and switched through nonlinear symmetry breaking by varying gain and loss parameters.
Abstract: We study nonlinear binary arrays composed of parity-time-symmetric optical waveguides with gain and loss. We demonstrate that such nonlinear binary lattices support stable discrete solitons, which can be adiabatically tuned and switched through nonlinear symmetry breaking by varying gain and loss parameters.
126 citations
TL;DR: Under cylindrically symmetric light-matter interaction, the radially, azimuthally, and spirally polarized eigen-modes for the light field are revealed to be of a fundamental interest to describe the physical mechanisms at work when dealing with scalar and vectorial optical singularities.
Abstract: We describe how the propagation of light through uniaxial crystals can be used as a versatile tool towards the spatial engineering of polarization and phase, thereby providing an all-optical technique for vectorial and scalar singular beam shaping in optics. Besides the prominent role played by the linear birefringence, the influence of circular birefringence (the optical activity) is discussed as well and both the monochromatic and polychromatic singular beam shaping strategies are addressed. Under cylindrically symmetric light-matter interaction, the radially, azimuthally, and spirally polarized eigen-modes for the light field are revealed to be of a fundamental interest to describe the physical mechanisms at work when dealing with scalar and vectorial optical singularities. In addition, we also report on nontrivial effects arising from cylindrical symmetry breaking, e.g. tilting the incident beam with respect to the crystal optical axis.
122 citations
TL;DR: Nonlinear plasmon self-focusing in tapered metal-dielectric-metal slot waveguides is studied and it is demonstrated that, by an appropriate choice of the taper angle, the mode attenuation can be suppressed achieving stable propagation of a spatial plAsmon soliton.
Abstract: We suggest using tapered waveguides for compensating losses of surface plasmon-polaritons in order to enhance nonlinear effects at the nanoscale. We study nonlinear plasmon self-focusing in tapered metal-dielectric-metal slot waveguides and demonstrate that, by an appropriate choice of the taper angle, we can effectively suppress the mode attenuation achieving stable propagation of a spatial plasmon soliton. For larger tapering angles we observe plasmon-beam nanofocusing in both spatial dimensions.
110 citations
TL;DR: In this article, the optical response and effective macroscopic parameters of fishnet metamaterials infiltrated with a nematic liquid crystal were analyzed numerically and it was shown that even a small amount of liquid crystal can provide tuning of the structures due to reorientation of the liquid crystal director.
Abstract: We analyze numerically the optical response and effective macroscopic parameters of fishnet metamaterials infiltrated with a nematic liquid crystal. We show that even a small amount of liquid crystal can provide tuning of the structures due to reorientation of the liquid crystal director. This enables switchable optical metamaterials, where the refractive index can be switched from positive to negative by an external field. This tuning is primarily determined by the shift of the cut-off wavelength of the holes, with only a small influence due to the change in plasmon dispersion
106 citations
TL;DR: A new approach for selective trapping of light absorbing particles in gases by multiple optical bottle-beam-like traps created by volume speckle field that acts as a sieve selecting particles of a similar size.
Abstract: We suggest a new approach for selective trapping of light absorbing particles in gases by multiple optical bottle-beam-like traps created by volume speckle field. We demonstrate stable simultaneous confinement of a few thousand micro-particles in air with a single low-power laser beam. The size distribution of trapped particles exhibits a narrow peak near the average size of an optical speckle. Thus, the speckle-formed traps act as a sieve with the holes selecting particles of a similar size.
TL;DR: In this article, the optical response and effective macroscopic parameters of fishnet metamaterials infiltrated with a nematic liquid crystal were analyzed numerically and it was shown that even a small amount of liquid crystal can provide tuning of the structures due to reorientation of the liquid crystal director.
Abstract: We analyze numerically the optical response and effective macroscopic parameters of fishnet metamaterials infiltrated with a nematic liquid crystal. We show that even a small amount of liquid crystal can provide tuning of the structures due to reorientation of the liquid crystal director. This enables switchable optical metamaterials, where the refractive index can be switched from positive to negative by an external field. This tuning is primarily determined by the shift in the cut-off wavelength of the holes, with only a small influence due to the change in plasmon dispersion.
TL;DR: In this paper, the first experimental observation of dynamic localization of light in two-dimensional photonic lattices was reported, where suppression of beam diffraction in hexagonal lattices created by weakly coupled waveguides with axis bending was demonstrated.
Abstract: We report on the first experimental observation of dynamic localization of light in two-dimensional photonic lattices. We demonstrate suppression of beam diffraction in hexagonal lattices created by weakly coupled waveguides with axis bending. We also reveal that this effect is strongly related to dynamic localization in zigzag waveguide arrays with next-nearest neighboring interactions.
TL;DR: In this article, the authors demonstrate a chiral electromagnetic diode, which is a direct analogue of an electronic diode and its functionality is underpinned by an extraordinary strong nonlinear wave propagation effect.
Abstract: An electronic diode is a nonlinear semiconductor circuit component that allows conduction of electrical current in one direction only. A component with similar functionality for electromagnetic waves, an electromagnetic isolator, is based on the Faraday effect of the polarization state rotation and is also a key component of optical and microwave systems. Here we demonstrate a chiral electromagnetic diode, which is a direct analogue of an electronic diode: its functionality is underpinned by an extraordinary strong nonlinear wave propagation effect in the same way as electronic diode function is provided by a nonlinear current characteristic of a semiconductor junction. The effect exploited in this new electromagnetic diode is an intensity-dependent polarization change in an artificial chiral metamolecule. This microwave effect exceeds a similar optical effect previously observed in natural crystals by more than 12 orders of magnitude and a direction-dependent transmission that differing by a factor of 65.
TL;DR: In this article, the authors demonstrate how to achieve reversible non-reciprocal optical response in a periodic photonic structure with a pair of defects, one of them being a nonlinear liquid crystal defect layer.
Abstract: We demonstrate how to achieve reversible nonreciprocal optical response in a periodic photonic structure with a pair of defects, one of them being a nonlinear liquid crystal defect layer. The twin defect structure is symmetric at low intensity and becomes asymmetric above an intensity threshold that corresponds to the optical reordering of the liquid crystal. We show that nonreciprocal effects can be reversed by changing the wavelength as a consequence of the wavelength dependent light localization at the defect mode inside the structure.
TL;DR: It is revealed that orbital angular momentum can suppress catastrophic self-focusing in nonlinear Kerr media supporting stable spiraling solitons with an elliptic cross section.
Abstract: We reveal that orbital angular momentum can suppress catastrophic self-focusing in nonlinear Kerr media supporting stable spiraling solitons with an elliptic cross section. We discuss the necessary requirements for observation of this effect with coherent optical and matter waves.
TL;DR: In this paper, the authors consider vibrational states localized at the edges of graphene nanoribbons and demonstrate that surface modes correspond to phonons localized at edges of the graphene nanoreibbons.
Abstract: We study vibrational states localized at the edges of graphene nanoribbons Such surface oscillations can be considered as a phonon analog of Tamm states in the electronic theory We consider both armchair and zigzag graphene stripes and demonstrate that surface modes correspond to phonons localized at the edges of the graphene nanoribbon, and they can be classified as in-plane and out-of-plane modes In armchair nanoribbons anharmonic edge modes can experience longitudinal localization in the form of self-localized nonlinear modes or surface breather solitons
TL;DR: In this paper, the nonlinear modes of plasmonic directional couplers created by two nonlinear dielectric slot waveguides with metallic claddings are studied.
Abstract: A study on the nonlinear modes of plasmonic directional couplers created by two nonlinear dielectric slot waveguides with metallic claddings is presented. The calculated power diagram shows substantial differences from the case of nonlinear dielectric couplers. The power-dependent switching and the effect of losses on the coupler performance are studied using finite-difference time-domain numerical simulations.
TL;DR: This work reveals that, while weak nonlinearity does not change the typical exponentially small transmission in the regime of the Anderson localization, it affects dramatically the disorder-induced localized states excited inside the medium leading to bistable and nonreciprocal resonant transmission.
Abstract: We study wave transmission through one-dimensional random nonlinear structures and predict a novel effect resulting from an interplay of nonlinearity and disorder. We reveal that, while weak nonlinearity does not change the typical exponentially small transmission in the regime of the Anderson localization, it affects dramatically the disorder-induced localized states excited inside the medium leading to bistable and nonreciprocal resonant transmission. Our numerical modeling shows an excellent agreement with theoretical predictions based on the concept of a high-Q resonator associated with each localized state. This offers a new way for all-optical light control employing statistically homogeneous random media without regular cavities.
TL;DR: It is demonstrated that the continuum generation process is initiated by the filamentation of the vortex, resulting in a spatially divergent continuum.
Abstract: We employ an optical vortex beam for the generation of femtosecond supercontinuum in a solid state medium. We demonstrate that the continuum generation process is initiated by the filamentation of the vortex, resulting in a spatially divergent continuum. Despite the strong self-focusing and the formation of multiple hot-spots along the vortex ring, the singularity is preserved in both the near- and far-fields.
TL;DR: Minovich, Neshev, Lapine, McKerracher, and Kivshar as mentioned in this paper used nonlinear physics at the Australian National University (ANU), Canberra, Australian Capital Territory 0200, Australia.
Abstract: Alexander Minovich,1 Dragomir N. Neshev,1 David A. Powell,1 Ilya V. Shadrivov,1 Mikhail Lapine,1,2 Ian McKerracher,3 Haroldo T. Hattori,4 Hark Hoe Tan,3 Chennupati Jagadish,3 and Yuri S. Kivshar1 1Nonlinear Physics Centre, Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200, Australia 2Department of Electronics and Electromagnetics, Faculty of Physics, University of Seville, Avenida Reina Mercedes s/n, 41012 Sevilla, Spain 3Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200, Australia 4School of Engineering and Information Technology, The Australian Defence Force Academy, University of New South Wales, Canberra, Australian Capital Territory 2600, Australia Received 28 September 2009; revised manuscript received 18 December 2009; published 5 March 2010
01 Jan 2010
TL;DR: Nonlinear effects in reduced-dimensional structures: From Wave Guide Arrays to Slow Light- Nonlinear Effects in One-Dimensional Photonic Lattices, Nonlinear Optical Waves in Liquid CrystallineLattices and Nonlinear Optics and Solitons in Photonic Crystal Fibres as discussed by the authors.
Abstract: Nonlinear Effects in Reduced-Dimensional Structures: From Wave Guide Arrays to Slow Light- Nonlinear Effects in One-Dimensional Photonic Lattices- Nonlinear Optical Waves in Liquid Crystalline Lattices- Nonlinear Optics and Solitons in Photonic Crystal Fibres- Spatial Switching of Slow Light in Periodic Photonic Structures- Nonlinear Effects in Multidimensional Lattices: Solitons and Light Localization- to Solitons in Photonic Lattices- Complex Nonlinear Photonic Lattices: From Instabilities to Control- Light Localization by Defects in Optically Induced Photonic Structures- Polychromatic Light Localisation in Periodic Structures- Periodic Structures for Matter Waves: From Lattices to Ratchets- Bose-Einstein Condensates in 1D Optical Lattices: Nonlinearity and Wannier-Stark Spectra- Transporting Cold Atoms in Optical Lattices with Ratchets: Mechanisms and Symmetries- Atomic Bose-Einstein Condensates in Optical Lattices with Variable Spatial Symmetry- Symmetry and Transport in a Rocking Ratchet for Cold Atoms- Metamaterials: From Linear to Nonlinear Features- Optical Metamaterials: Invisibility in Visible and Nonlinearities in Reverse- Nonlinear Metamaterials- Circuit Model of Gain in Metamaterials- Discrete Breathers and Solitons in Metamaterials
TL;DR: In this paper, laser beams containing phase singularity can be used for trapping and guiding light-absorbing particles in air, and the particle position on the beams axis within the trap can be controlled by changing the relative intensity of two beams.
Abstract: In this paper we show that laser beams containing phase singularity can be used for trapping and guiding light-absorbing particles in air. The experiments were performed with agglomerates of carbon nanoparticles with the size in the range 0.1–10 μm; the typical cw laser power was of a few mW. The stability of open-air three-dimensional trapping was within ±2 μm in both the transverse and the longitudinal directions. The particle position on the beams axis within the trap can be controlled by changing the relative intensity of two beams. The distinguishing feature of the trapping strategy is that particles are trapped at the intensity minimum of the beam, thus with minimum heating and intervention into the particle properties, which is important for direct studies of particle properties and for air-trapping of living cells.
TL;DR: In this paper, the authors demonstrate that the presence of a supporting substrate can break the symmetry of a metamaterial structure, changing the symmetry and giving rise to bianisotropy.
Abstract: We demonstrate that the presence of a supporting substrate can break the symmetry of a metamaterial structure, changing the symmetry of its effective parameters, and giving rise to bianisotropy. This indicates that magnetoelectric coupling will occur in all metamaterials fabricated on a substrate, including those with symmetric designs.
TL;DR: It is demonstrated that when the nonlinear grating is illuminated simultaneously by two noncollinear beams, a second-harmonic diffraction pattern is generated by a virtual beam propagating along the bisector of the two pump beams.
Abstract: We observe experimentally a novel type of nonlinear diffraction in the process of two-wave mixing on a nonlinear quadratic grating. We demonstrate that when the nonlinear grating is illuminated simultaneously by two noncollinear beams, a second-harmonic diffraction pattern is generated by a virtual beam propagating along the bisector of the two pump beams. The observed diffraction phenomena is a purely nonlinear effect that has no analogue in linear diffraction.
TL;DR: It is demonstrated that the interaction of spatial optical solitons with curved dielectric surfaces in unbiased nematic liquid crystals depends on the curvature of the surface and the walk-off, and it can be employed for efficient routing and control of the soliton trajectories.
Abstract: We study experimentally the interaction of spatial optical solitons with curved dielectric surfaces in unbiased nematic liquid crystals. We demonstrate that this interaction depends on the curvature of the surface and the walk-off, and it can be employed for efficient routing and control of the soliton trajectories. We also observe a large-angle total internal reflection of the soliton beam from an interface between liquid crystal and air.
TL;DR: The dynamic instability of two counterpropagating nematicons in the form of time-dependent splitting and spatial entanglement is observed.
Abstract: We experimentally investigate the interaction of two counter-propagating spatial optical solitons (nematicons) in bias-free nematic liquid crystals. We demonstrate the existence of vector solitons composed of two nematicons propagating in opposite directions and analyze their stability versus relative distance and input power.We observe the dynamic instability of two counterpropagating nematicons in the form of time-dependent splitting and spatial entanglement.
TL;DR: In this paper, the authors revisited the problem of the existence of plasmonic modes guided by metal- dielectric-metal slot waveguides and classified the guided modes in the structure with the metal dispersion.
Abstract: We revisited the problem of the existence of plasmonic modes guided by metal- dielectric-metal slot waveguides. For the case of lossless slot waveguides, we classify the guided modes in the structure with the metal dispersion and found that, in a certain parameter range, three different guided modes coexist at a fixed frequency, two (symmetric and antisymmetric) forward propagating modes and the third, backward propagating antisymmetric mode. We study the properties of the forward and backward plasmonic guided modes in the presence of realistic losses, and discuss the importance of evanescent modes in lossy structures.
TL;DR: In this article, the authors demonstrate numerically that armchair graphene nanoribbons can support vibrational localized states in the form of surface solitons, and they find five types of such solitary waves including in-plane and out-of-plane edge breathers.
Abstract: We demonstrate numerically that armchair graphene nanoribbons can support vibrational localized states in the form of surface solitons. Such localized states appear through self-localization of the vibrational energy along the edge of the graphene nanoribbon, and they decay rapidly inside the structure. We find five types of such solitary waves including in-plane and out-of-plane edge breathers and moving envelope solitons.
TL;DR: In this paper, the authors demonstrate that a speckle pattern in the spatially coherent laser field transmitted by a diffuser forms a multitude of three-dimensional intensity micro-pockets acting as particle traps for air-borne light absorbing particles.
Abstract: We demonstrate that a speckle pattern in the spatially coherent laser field transmitted by a diffuser forms a multitude of three-dimensional intensity micro-pockets acting as particle traps for air-borne light absorbing particles. Confinement of up to a few thousand particles in air with a unidirectional single beam has been achieved. Theoretical analysis of the speckle defined trapping volume is in a good agreement with experimental results on capturing of aggregates of carbon nanoparticles in air.