Publications
468 results found
Huidobro PA, Chang YH, Kraft M, et al., 2017, Hidden symmetries in plasmonic gratings, PHYSICAL REVIEW B, Vol: 95, ISSN: 2469-9950
Arroyo-Huidobro P, Maier SA, Pendry, 2017, Tunable plasmonic metasurface for perfect absorption, EPJ Applied Metamaterials, Vol: 4, ISSN: 2272-2394
Tunable metasurfaces, whose functionality can be dynamically modified, open up the possibil-ity of ultra-compact photonic components with reconfigurable applications. Here we consider agraphene monolayer subject to a spatially periodic gate bias, which, thank to surface plasmons inthe graphene, acts as a tunable and extremely compact metasurface for terahertz radiation. Aftercharacterizing its functionality, we show that it serves as the basic building block of an ultrathincomplete absorber. In this subwavelength-thickness device, transmission and reflection channels areblocked and electromagnetic energy is completely absorbed by the metasurface building blocks. Theproposed structure can be used as a modulator, and its frequency of operation can be changed byscaling its size or adjusting the doping level.
Sasihithlu K, Pendry JB, Craster RV, 2017, Van der Waals Force Assisted Heat Transfer, Zeitschrift für Naturforschung - Section A Journal of Physical Sciences, Vol: 72, Pages: 181-188, ISSN: 0932-0784
Phonons (collective atomic vibrations in solids) are more effective in transporting heat than photons. This is the reason why the conduction mode of heat transport in nonmetals (mediated by phonons) is dominant compared to the radiation mode of heat transport (mediated by photons). However, since phonons are unable to traverse a vacuum gap (unlike photons), it is commonly believed that two bodies separated by a gap cannot exchange heat via phonons. Recently, a mechanism was proposed [J. B. Pendry, K. Sasihithlu, and R. V. Craster, Phys. Rev. B 94, 075414 (2016)] by which phonons can transport heat across a vacuum gap – through the Van der Waals interaction between two bodies with gap less than the wavelength of light. Such heat transfer mechanisms are highly relevant for heating (and cooling) of nanostructures; the heating of the flying heads in magnetic storage disks is a case in point. Here, the theoretical derivation for modelling phonon transmission is revisited and extended to the case of two bodies made of different materials separated by a vacuum gap. Magnitudes of phonon transmission, and hence the heat transfer, for commonly used materials in the micro- and nano-electromechanical industry are calculated and compared with the calculation of conduction heat transfer through air for small gaps as well as the heat transfer calculation due to photon exchange.
Pendry JB, 2016, Low frequency plasmons in thin-wire structures: a commentary., Journal of Physics: Condensed Matter, Vol: 28, ISSN: 0953-8984
Pendry JB, Sasihithlu K, Craster RV, 2016, Phonon-assisted heat transfer between vacuum-separated surfaces, Physical Review B - Condensed Matter and Materials Physics, Vol: 94, ISSN: 1098-0121
With increasing interest in nanotechnology, the question arises of how heat is exchanged between materials separated by only a few nanometers of vacuum. Here, we present calculations of the contribution of phonons to heat transfer mediated by van der Waals forces and compare the results to other mechanisms such as coupling through near field fluctuations. Our results show a more dramatic decay with separation than previous work.
Pendry JB, 2016, Controlling nanoscale light (Conference Presentation), Conference on Metamaterials X, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Our intuitive understanding of light has its foundation in the ray approximation and is intimately connected with our vision: as far as our eyes are concerned light behaves like a stream of particles. Here we look inside the wavelength and study the properties of plasmonic structures with dimensions of just a few nanometres: a tenth or even a hundredth of the wavelength of visible light, where the ray picture fails utterly. In this talk we show how the new concept of transformation optics that manipulates electric and magnetic field lines rather than rays can provide an equally intuitive understanding of sub wavelength phenomena and at the same time be an exact description at the level of Maxwell’s equations. The concepts are applied to a number of plasmonic structures
Kraft M, Luo Y, Pendry JB, 2016, Transformation Optics: A Time- and Frequency-Domain Analysis of Electron-Energy Loss Spectroscopy., Nano Letters, Vol: 16, Pages: 5156-5162, ISSN: 1530-6992
Electron energy loss spectroscopy (EELS) and cathodoluminescence (CL) play a pivotal role in many of the cutting edge experiments in plasmonics. EELS and CL experiments are usually supported by numerical simulations, which-though accurate-may not provide as much physical insight as analytical calculations do. Fully analytical solutions to EELS and CL systems in plasmonics are rare and difficult to obtain. This paper aims to narrow this gap by introducing a new method based on transformation optics that allows to calculate the quasistatic frequency- and time-domain response of plasmonic particles under electron beam excitation. We study a nonconcentric annulus (and ellipse in the Supporting Information ) as an example.
Kraft M, Braun A, Luo Y, et al., 2016, Bianisotropy and magnetism in plasmonic gratings, ACS Photonics, Vol: 3, Pages: 764-769, ISSN: 2330-4022
We present a simple design to achieve bianisotropy at visible wavelengths: an ultrathinplasmonic grating made of a gold grating covered by a thin flat layer of gold.We show experimentally and through simulations that the grating exhibits magnetoelectriccoupling and features asymmetric reflection and absorption, all that with adevice thickness of a tenth of the operating wavelength. We compared the spectralresults and retrieved the effective material parameters of different polarizations anddevices. We show that both asymmetry and strong coupling between the incominglight and the optically interacting surfaces are required for obtaining asymmetric opticalbehavior in metasurfaces
Huidobro PA, Kraft M, Maier SA, et al., 2016, Graphene as a Tunable Anisotropic or IsotropicPlasmonic Metasurface, ACS Nano, Vol: 10, Pages: 5499-5506, ISSN: 1936-086X
We demonstrate a tunable plasmonic metasurface by considering a graphene sheetsubject to a periodically patterned doping level. The unique optical properties ofgraphene result in electrically tunable plasmons that allow for extreme confinementof electromagnetic energy in the technologically significant regime of THz frequencies.Here we add an extra degree of freedom by using graphene as a metasurface, proposingto dope it with an electrical gate patterned in the micron or sub-micron scale. Byextracting the effective conductivity of the sheet we characterize metasurfaces periodicallymodulated along one or two directions. In the first case, and making use of theanalytical insight provided by transformation optics, we show an efficient control ofTHz radiation for one polarization. In the second case, we demonstrate a metasurfacewith an isotropic response that is independent of wave polarization and orientation.
Arroyo Huidobro P, Kraft M, Ren K, et al., 2016, Graphene, plasmons and transformation optics, Journal of Optics, Vol: 18, ISSN: 2040-8978
Here we study subwavelength gratings for coupling into graphene plasmons by means of an an-alytical model based on transformation optics that is not limited to very shallow gratings. Weconsider gratings that consist of a periodic modulation of the charge density in the graphene sheet,and gratings formed by this conductivity modulation together with a dielectric grating placed inclose vicinity of the graphene. Explicit expressions for the dispersion relation of the plasmon po-laritons supported by the system, and reectance and transmittance under plane wave illuminationare given. We discuss the conditions for maximising the coupling between incident radiation andplasmons in the graphene, finding the optimal modulation strength for a conductivity grating.
Chen H, Pendry JB, Smith DR, 2016, Special issue on transformation optics, Journal of Optics, Vol: 18, ISSN: 2040-8986
Bak AO, Yoxall EO, Sarriugarte P, et al., 2016, Harnessing a Quantum Design Approach for Making Low-Loss Superlenses, NANO LETTERS, Vol: 16, Pages: 1609-1613, ISSN: 1530-6984
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- Citations: 6
Zhao R, Luo Y, Pendry JB, 2016, Transformation optics applied to van der Waals interactions, SCIENCE Bulletin, Vol: 61, Pages: 59-67, ISSN: 2095-9273
The van der Waals force originates from the electromagnetic interaction between quantum fluctuation-induced charges. It is a ubiquitous but subtle force which plays an important role and has a wide range of applications in surface related phenomena like adhesion, friction, and colloidal stability. Calculating the van der Waals force between closely spaced metallic nanoparticles is very challenging due to the strong concentration of electromagnetic fields at the nanometric gap. Especially, at such a small length scale, the macroscopic description of the dielectric properties no longer suffices. The diffuse nonlocal nature of the induced surface electrons which are smeared out near the boundary has to be considered. Here, we review the recent progress on using three-dimensional transformation optics to study the van der Waals forces between closely spaced nanostructures. Through mapping a seemingly asymmetric system to a more symmetric counterpart, transformation optics enables us to look into the behavior of van der Waals forces at extreme length scales, where the effect of nonlocality is found to dramatically weaken the van der Waals interactions.
Kraft M, Luo Y, Pendry JB, 2016, Transformation Optics and EELS, a Frequency- and Time-domain Analysis, Progress in Electromagnetic Research Symposium (PIERS), Publisher: IEEE, Pages: 1702-1706
Huidobro PA, Kraft M, Maier SA, et al., 2016, Graphene as a Tunable Plasmonic Metasurface with Transformation Optics, Progress in Electromagnetic Research Symposium (PIERS), Publisher: IEEE, Pages: 14-14
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- Citations: 1
Schaich WL, 2015, Comment on "Surface Plasmons and Nonlocality: A Simple Model"., Phys Rev Lett, Vol: 115
A Comment on the Letter by Y. Luo, A. I. Fernandez-Dominguez, A. Wiener, S. A. Maier, and J. B. Pendry, Phys. Rev. Lett. 111, 093901 (2013).. The authors of the Letter offer a Reply.
Luo Y, Fernandez-Dominguez AI, Wiener A, et al., 2015, Reply to "Comment on “Surface Plasmons and Nonlocality: A Simple Model”, Physical Review Letters, Vol: 115, ISSN: 1079-7114
Schaich WL, Luo Y, Fernandez-Dominguez AI, et al., 2015, Comment on "Surface Plasmons and Nonlocality: A Simple Model", PHYSICAL REVIEW LETTERS, Vol: 115, ISSN: 0031-9007
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- Citations: 4
Kraft M, Luo Y, Maier SA, et al., 2015, Designing plasmonic gratings with transformation optics, Physical Review X, Vol: 5, ISSN: 2160-3308
Plasmonic gratings that support both localized and propagating plasmons have wide applications in solar cells and optical biosensing. In this paper, we report on a most unusual grating designed to capture light efficiently into surface plasmons and concentrate their energy at hot spots where the field is resonantly enhanced. The dispersion of the surface plasmons shows degeneracy points at k=0, where, despite a strongly modulated grating, hidden symmetries forbid hybridization of plasmons traveling in opposite directions.
Pendry JB, Luo Y, Zhao R, 2015, Transforming the optical landscape, Science, Vol: 348, Pages: 521-524, ISSN: 0036-8075
Electromagnetism provides us with some of the most powerful tools in science, encompassing lasers, optical microscopes, magnetic resonance imaging scanners, radar, and a host of other techniques. To understand and develop the technology requires more than a set of formal equations. Scientists and engineers have to form a vivid picture that fires their imaginations and enables intuition to play a full role in the process of invention. It is to this end that transformation optics has been developed, exploiting Faraday’s picture of electric and magnetic fields as lines of force, which can be manipulated by the electrical permittivity and magnetic permeability of surrounding materials. Transformation optics says what has to be done to place the lines of force where we want them to be.
Fernandez-Dominguez AI, Liu Z, Pendry JB, 2015, Coherent Four-Fold Super-Resolution Imaging with Composite Photonic-Plasmonic Structured Illumination, ACS PHOTONICS, Vol: 2, Pages: 341-348, ISSN: 2330-4022
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- Citations: 28
Pendry JB, 2015, Nonlinear, Tunable and Active Metamaterials Foreword, NONLINEAR, TUNABLE AND ACTIVE METAMATERIALS, Editors: Shadrivov, Lapine, Kivshar, Publisher: SPRINGER-VERLAG BERLIN, Pages: V-VI, ISBN: 978-3-319-08385-8
Huidobro PA, Moreno E, Martin-Moreno L, et al., 2015, Magnetic Localized Surface Plasmons Supported by Metal Structures, 9th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics (METAMATERIALS), Publisher: IEEE, Pages: 13-15
Luo Y, Pendry JB, 2015, Controlling Light at the Subwavelength Scale, IEEE 4th Asia Pacific Conference Antennas Propagation, Publisher: IEEE, Pages: 30-31, ISSN: 2381-5523
Luo Y, Zhao R, Pendry JB, 2014, van der Waals interactions at the nanoscale: The effects of nonlocality, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 111, Pages: 18422-18427, ISSN: 0027-8424
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- Citations: 83
Pendry JB, 2014, Controlling Light on the Nanoscale, PROGRESS IN ELECTROMAGNETICS RESEARCH-PIER, Vol: 147, Pages: 117-126, ISSN: 1559-8985
Kraft M, Pendry JB, Maier SA, et al., 2014, Transformation optics and hidden symmetries, PHYSICAL REVIEW B, Vol: 89, ISSN: 2469-9950
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- Citations: 24
Huidobro PA, Shen X, Cuerda J, et al., 2014, Magnetic Localized Surface Plasmons, Physical Review X, Vol: 4, ISSN: 2160-3308
Here, we introduce the concept of magnetic localized surface plasmons (LSPs), magnetic dipole modes that are supported by cylindrical metal structures corrugated by very long, curved grooves. The resonance wavelength is dictated by the length of the grooves, allowing us to tune it to values much larger than the size of the particle. Moreover, magnetic LSPs also exist for extremely thin metal disks and, therefore, they could be used to devise metasurfaces with magnetic functionalities. Experimental evidence of the existence of these magnetic LSPs in the microwave regime is also presented, although the concept is very general and could be applied to terahertz or infrared frequencies.
Luo Y, Zhao R, Fernandez-Dominguez A, et al., 2013, Harvesting light with transformation optics, SCIENCE CHINA-INFORMATION SCIENCES, Vol: 56, ISSN: 1674-733X
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- Citations: 28
Wiener A, Fernandez-Dominguez AI, Pendry JB, et al., 2013, Nonlocal propagation and tunnelling of surface plasmons in metallic hourglass waveguides, OPTICS EXPRESS, Vol: 21, Pages: 27509-27518, ISSN: 1094-4087
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- Citations: 12
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