Surface plasmons (SPs) are key excitations for manipulating light in two dimensions, as in integrated optical circuits on chips. Here the authors show how to filter, in selected directions, the signal due to SP motion in a collimating device. Considering both the classical and quantum optical regimes, they interpret their findings in terms of a propagative electromagnetic local density of states. This approach could also be used in other quantum-technology contexts, $e.g.$ to optimize the coupling efficiency of quantum emitters.

[Phys. Rev. Applied 7, 014021] Published Fri Jan 27, 2017

An experimental setup based on a modified scanning electron microscope is used to explore fundamental aspects of the coupling of free electrons to plasmonic crystals and localized plasmonic resonances.

[Phys. Rev. X 7, 011003] Published Tue Jan 17, 2017

Compensating loss and amplifying surface plasmons in deep-subwavelength waveguide structures are of great interest across fields including optoelectronics, optical telecommunication, metamaterials, and chemical sensing. However, $stimulated$ emission in the gain medium inevitably comes with $spontaneous$ emission, which greatly increases noise. The authors establish a comprehensive quantum-optics framework to evaluate the influence of spontaneous-emission noise, even when the emission spectrum is broad and nonuniform. They find substantial differences from previously reported analyses.

[Phys. Rev. Applied 6, 064024] Published Thu Dec 29, 2016

Substituting noble metals for high-index dielectrics has recently been proposed as an alternative strategy in nanophotonics, to design broadband optical resonators and circumvent the ohmic losses of plasmonic materials. On the other hand, the authors show that subwavelength silicon nanoantennas can either enhance or inhibit spontaneous emission from fluorescent molecules, a process that is inaccessible with noble metals at the nanoscale. This study highlights the potential of dielectric resonators for low-loss near-field manipulation of solid-state emitters, at room temperature.

[Phys. Rev. Applied 6, 064016] Published Wed Dec 28, 2016

Metasurfaces (metamaterials of near-vanishing thickness) are of interest for engineering subwavelength structures with complex responses. Typically a graphene metasurface exhibits just one or two resonances and absorbs light in a narrow frequency band, but this study demonstrates tunable broadband absorption due to hierarchical, fractal structuring. Over a very wide band (about 190% of the central frequency), the average absorption exceeds 20%, without any metallic mirror. This approach to broadband absorbers, and plasmonic components more generally, offers substantially improved performance at terahertz and optical frequencies.

[Phys. Rev. Applied 6, 044019] Published Fri Oct 28, 2016

The visible luminescence related to crystalline defects in wide-band-gap semiconductors like zinc oxide could be employed in LEDs, but emission intensity saturates at high power, due to the filling of defect states with excited carriers. This is a critical problem for high-power applications of LEDs, including solid-state lighting. The author shows how to avoid this saturation and enhance emission by exploiting a plasmonic effect: When surface plasmons form in adjacent metal nanostructures, they facilitate carrier recombination in the semiconductor, which keeps the defect states from filling up.

[Phys. Rev. Applied 6, 044009] Published Mon Oct 17, 2016

Nonuniform metasurfaces (electrically thin composite layers) can be used for shaping refracted and reflected electromagnetic waves. However, known design approaches based on the generalized refraction and reflection laws do not allow realization of perfectly performing devices: there are always some…

[Phys. Rev. B 94, 075142] Published Fri Aug 19, 2016

We propose to understand surface-enhanced Raman scattering (SERS) as a higher-order Raman process that contains the plasmonic excitation. The SERS amplitudes are calculated with third- and fourth-order perturbation theory. Treating the plasmonic excitation as a quasiparticle, we derive analytic expr…

[Phys. Rev. A 94, 023813] Published Thu Aug 04, 2016

One of graphene’s interesting properties is that, when pumped by a laser at near-infrared and visible frequencies, it offers amplification at terahertz (THz) frequencies, which are useful for remote sensing in security applications. The authors explain how to take advantage of exotic parity-time ($PT$) symmetry in an active graphene metasurface that realizes reciprocal, unidirectional reflectionless propagation of THz waves. This suggests exciting prospects for detecting chemical and biological agents with ultrahigh sensitivity.

[Phys. Rev. Applied 5, 064018] Published Wed Jun 29, 2016

Light-matter interactions often depend on the light’s state of polarization (SOP), but actually measuring this SOP can be difficult, as the phase information between orthogonal polarization states is completely lost in conventional, intensity-based, detection. Using multiple birefringent plasmonic metasurfaces, the authors propose a compact polarimeter that is well suited for in-plane optical circuitry and allows facile determination of the SOP, as illustrated for the telecommunication wavelength of 1550 nm.

[Phys. Rev. Applied 5, 064015] Published Mon Jun 27, 2016

The excitation of cavity standing waves in double-slit structures in thin gold films, with slit lengths between 400 and 2560 nm, was probed with a strongly focused electron beam in a transmission electron microscope. The energies and wavelengths of cavity modes up to the $11\mathrm{th}$ mode order were measure…

[Phys. Rev. B 93, 245417] Published Fri Jun 17, 2016

A lossy anisotropic epsilon-near-zero (ENZ) medium may lead to a counterintuitive phenomenon of omnidirectional bending-to-normal refraction [S. Feng, Phys. Rev. Lett. 108, 193904 (2012)], which offers a fabulous strategy for energy collimation and energy harvesting. Here, in the scope of effective …

[Phys. Rev. B 93, 245118] Published Wed Jun 08, 2016

An alternative approach of using a distributed transmission line analogy for solving transport equations for ballistic nanostructures is applied for solving the three-dimensional problem of electron transport in gated ballistic nanostructures with periodically changing width. The structures with var…

[Phys. Rev. B 93, 195315] Published Wed May 25, 2016

Multiscale plasmonic systems (e.g., extended metallic nanostructures with subnanometer inter-distances) play a key role in the development of next-generation nanophotonic devices. An accurate modeling of the optical interactions in these systems requires an accurate description of both quantum effec…

[Phys. Rev. B 93, 205405] Published Wed May 04, 2016

Conventional solar cells cannot collect energy from abundant midinfrared light, because there are no suitable semiconductors of the right band gap. Hyperbolic metamaterials (HMMs) are proposed to realize broadband, omnidirectional, sensitive diodes operating in this spectral region. The authors show how the slow-light modes supported by HMMs can trap incident radiation in metal-insulator-metal tunnel junctions, for ultrafast optical rectification and photon-to-electron energy conversion that is orders of magnitude more efficient than in conventional optical rectennas.

[Phys. Rev. Applied 5, 041001] Published Thu Apr 28, 2016

We demonstrate that ultrafast carrier excitation can drastically affect electronic structures in nonplasmonic metals and determine a transient, brief surface plasmonic state, potentially creating the conditions for a plasmonic switch. The initial state can be related to $d$-band partial filling and sp…

[Phys. Rev. B 93, 165416] Published Thu Apr 14, 2016

Currently, there is great interest in the field of “active plasmonics”, where the properties of plasmonic excitations are tuned by an external stimulus. For practical applications, fast and efficient operation is required. Lattice vibrations in the plasmonic medium enable high-frequency modulation. So far, optical control by lattice vibrations was developed for the case of acoustic phonons only, which limits the operation frequencies to the gigaheretz range. Here, the authors go beyond this limit and demonstrate how optical phonons can be efficiently used for high-frequency terahertz modulation of light at the nanoscale. This is achieved by using novel hybrid plasmonic-semiconductor structures, wherein the modulation takes place in a nanometer-thin layer of elemental tellurium that forms under illumination by intense laser pulses.

[Phys. Rev. B 93, 125404] Published Thu Mar 03, 2016

Ultrasensitive detection of nanoscale particles has applications in important fields ranging from environmental monitoring to analysis of viral structures. The authors show that the dissipative interaction in an optical microcavity of high quality factor allows the detection of single nanoparticles, even when the real part of an analyte’s polarizability approaches zero. This innovative approach presents a significant step towards practical optical sensors for use in physics, analytical chemistry, environmental science, and molecular biology.

[Phys. Rev. Applied 5, 024011] Published Fri Feb 26, 2016

Plasmonic nanoatennas are a versatile tool for coherently manipulating light on a nanoscale by confining electric fields of the driving laser into subwavelength volumes, thereby significantly enhancing electric near fields. It is normally assumed that the time-dependent spectral properties of these …

[Phys. Rev. A 93, 021405(R)] Published Wed Feb 24, 2016

We investigate the scattering properties of two-dimensional high-aspect-ratio metal trenches acting as resonators for gap-surface plasmons and show that these resonators are highly efficient scatterers of free waves, reaching at resonance in the perfect-conductor limit the unitary dipolar limit for …

[Phys. Rev. B 93, 075413] Published Thu Feb 04, 2016

Thin films are central to modern technologies ranging from semiconductors to metamaterials. The authors observe that by placing a subwavelength thin film at the node of an electromagnetic standing wave, it is possible to separate electric from magnetic dipole terms, or dipole from quadrupole terms, in the absorption spectrum. The technique is twice as sensitive as conventional measurements, functions at very low laser power, and reveals resonances that are invisible to existing spectroscopies. This approach could see application in analytical chemistry, condensed matter physics, nanotechnology, and forensic science.

[Phys. Rev. Applied 5, 014010] Published Wed Jan 27, 2016

As electronics continue to shrink, heat management at the nanoscale has become increasingly important. The authors show that the thermal conductance at a metal-dielectric interface can be improved by half an order of magnitude by inserting just 1 nm of another metal. Multifunctional interfaces, as in plasmonic applications for heat-assisted magnetic recording, could exploit this thermal benefit with little impact on other properties.

[Phys. Rev. Applied 5, 014009] Published Tue Jan 26, 2016

We consider scattering of surface plasmon polaritons (SPPs) and light by individual high refractive index dielectric nanoparticles (NPs) located on a metal (gold) substrate and supporting electric and magnetic dipole resonances in the visible spectral range. Numerical calculations are carried out by…

[Phys. Rev. B 92, 245419] Published Mon Dec 14, 2015

The ideal black body fully absorbs all incident rays, that is, all propagating waves created by arbitrary sources. A known idealized realization of the black body is the perfectly matched layer (PML), widely used in numerical electromagnetics. However, ideal black bodies and PMLs do not interact wit…

[Phys. Rev. B 92, 245402] Published Tue Dec 01, 2015

[Phys. Rev. B 92, 199906] Published Wed Nov 25, 2015

Optical phase-array antennas can be used to control fluorescence from quantum emitters. The intensity distribution and polarization of the resulting emission are determined by the properties of the antenna and the emitters, and the strength of the antenna-emitter coupling. The authors show how Fourier polarimetry can be used to characterize and understand these three contributions, particularly the coupling, in an important step for engineering plasmonic systems.

[Phys. Rev. Applied 4, 054014] Published Wed Nov 25, 2015

The radiation dynamics of optical emitters can be manipulated by properly designed material structures modifying local density of photonic states, a phenomenon often referred to as the Purcell effect. Plasmonic nanorod metamaterials with hyperbolic dispersion of electromagnetic modes are believed to…

[Phys. Rev. B 92, 195127] Published Mon Nov 16, 2015

Advances in theory are needed to match recent progress in measurements of coupled semiconductor resonators supporting terahertz plasmons. Here, we present a field-based model of plasmonic resonators that comprise gated and ungated two-dimensional electron systems. The model is compared to experiment…

[Phys. Rev. B 92, 195304] Published Mon Nov 09, 2015

Interactions between molecules and light modes can alter the chemical structures of molecules. By examining strong coupling from a microscopic perspective it is possible to predict the modifications that molecules will undergo.

[Phys. Rev. X 5, 041022] Published Mon Nov 09, 2015

Many of tomorrow’s photonic devices, including optical biosensors, may rely on light signals with highly particular polarization properties. A new experiment shows that an ultrathin layer of gold particles can selectively absorb or reflect a light beam depending on its polarization handedness.

[Phys. Rev. X 5, 041019] Published Wed Nov 04, 2015

We discuss three formally different formulas for normalization of quasinormal modes currently in use for modeling optical cavities and plasmonic resonators and show that they are complementary and provide the same result. Regardless of the formula used for normalization, one can use the norm to defi…

[Phys. Rev. A 92, 053810] Published Wed Nov 04, 2015

We demonstrate that use of the field effect enables tuning of the effective optical parameters of a layered hyperbolic metamaterial at optical frequencies. Field-effect gating electrically modulates the permittivity in transparent conductive oxides via changes in the carrier density. These permittiv…

[Phys. Rev. B 92, 184101] Published Mon Nov 02, 2015

Transparent conductors (TCs) combine the usually contraindicated properties of electrical conductivity with optical transparency and are generally made by starting with a transparent insulator and making it conductive via heavy doping, an approach that generally faces severe “doping bottlenecks.” We…

[Phys. Rev. Lett. 115, 176602] Published Fri Oct 23, 2015

Engineering collective excitations such as plasmons and polaritons provides access to exotic optical properties. This study reports semiconductor nanostructures with coupled surface modes that interact with multiple resonant dipoles, yielding double and triple polariton branches in the system’s response. This produces useful and tunable properties with the flexibility to enable low-voltage tunable filters, light-emitting diodes, and efficient nonlinear composite materials.

[Phys. Rev. Applied 4, 044011] Published Tue Oct 20, 2015

We show that a single quantum emitter can efficiently couple to the tunable plasmons of a highly doped single-wall carbon nanotube (SWCNT). Plasmons in these quasi-one-dimensional carbon structures exhibit deep subwavelength confinement that pushes the coupling efficiency close to 100% over a very b…

[Phys. Rev. Lett. 115, 173601] Published Tue Oct 20, 2015

Terahertz surface plasmons are realized experimentally via diffraction of a vortex beam from a metal-dielectric interface.

[Phys. Rev. Lett. 115, 163901] Published Wed Oct 14, 2015

We study cascaded harmonic generation of hybrid surface plasmons in integrated planar waveguides composed of a graphene layer and a doped-semiconductor slab. We derive a comprehensive model of cascaded third-harmonic generation through phase-matched nonlinear interaction of fundamental, second-harmo…

[Phys. Rev. B 92, 155410] Published Wed Oct 07, 2015

We clarify analytically and numerically the physical origin and the behavior of the Norton field scattered by a narrow slit, at optical frequencies. This apparent surface field, which comes in addition to the surface plasmon-polariton and classic cylindrical light waves, features its own radiation l…

[Phys. Rev. B 92, 155404] Published Mon Oct 05, 2015

We study theoretically and experimentally coherent imaging of surface plasmon polaritons using either leakage radiation microscopy through a thin metal film or interference microscopy through a thick metal film. Using a rigorous modal formalism based on scalar Whittaker potentials, we develop a syst…

[Phys. Rev. E 92, 033202] Published Mon Sep 28, 2015

We model the quantum dynamics of two, three, or four quantum dots (QDs) in proximity to a plasmonic system such as a metal nanoparticle or an array of metal nanoparticles. For all systems, an initial state with only one QD in its excited state evolves spontaneously into a state with entanglement bet…

[Phys. Rev. B 92, 125432] Published Wed Sep 23, 2015

Quantum effects of plasmonic phenomena have been explored through ab initio studies, but only for exceedingly small metallic nanostructures, leaving most experimentally relevant structures too large to handle. We propose instead an effective description with the computationally appealing features of…

[Phys. Rev. Lett. 115, 137403] Published Wed Sep 23, 2015

Nonlinear metasurfaces based on coupling a locally enhanced plasmonic response to intersubband transitions of $n$-doped multi-quantum-wells (MQWs) can provide second-order susceptibilities orders of magnitude larger than any other nonlinear flat structure measured so far. Here we present a comprehensi…

[Phys. Rev. B 92, 125429] Published Mon Sep 21, 2015

Using a scattered field interference mechanism, we theoretically demonstrate the quantum statistics control with a hybrid system comprised of a quantum emitter and a plasmonic multimode nanocavity. Enhanced through multimode interactions, destructive interference between scattered fields from the em…

[Phys. Rev. A 92, 033836] Published Fri Sep 18, 2015

A 97% decrease in the normalized transmission of THz pulses is observed through subwavelength openings in van der Waals materials —- layered 2D materials with graphene-like properties.

[Phys. Rev. Lett. 115, 125501] Published Wed Sep 16, 2015

We theoretically examine the role of Kerr nonlinearities for graphene plasmonics in nanostructures, specifically in nanoribbons. The nonlinear Kerr interaction is included semiclassically in the intraband approximation. The resulting electromagnetic problem is solved numerically by self-consistent i…

[Phys. Rev. B 92, 121407(R)] Published Wed Sep 16, 2015

Electronic excitations in metallic nanoparticles in the optical regime that have been of great importance in surface-enhanced spectroscopy and emerging applications of molecular plasmonics, due to control and confinement of electromagnetic energy, may also be of potential to control the motion of na…

[Phys. Rev. A 92, 033416] Published Mon Sep 14, 2015

Solar cell technology benefits from increased photocurrents. New research uses transformation optics to preferentially concentrate light in hotspots in a metal grating.

[Phys. Rev. X 5, 031029] Published Tue Sep 08, 2015

Spies and wizards, take note: The authors provide an overview of the recent efforts in metamaterial technology devoted to cloaking, as well as a perspective on the future of this rapidly changing field. The potential of passive cloaking techniques is outlined, as is the possibility of overcoming their limitations using active or nonlinear cloaks.

[Phys. Rev. Applied 4, 037001] Published Tue Sep 01, 2015

Incandescent sources typically emit broadband light in all directions. Most of this radiation is lost for applications in the infrared region, such as spectroscopy or compositional analysis. Here the authors control both the spatial and temporal coherence of blackbody radiation with a plasmonic metasurface that emits a narrow band of frequencies in a small solid angle. This system operates reliably at 600 °C using CMOS-compatible materials, inviting the development of compact, efficient, and cheap infrared sources and gas detectors.

[Phys. Rev. Applied 4, 014023] Published Thu Jul 30, 2015

An array of helical elements absorbs radiation of a certain frequency while casting no shadow in light over a range of other frequencies.

[Phys. Rev. X 5, 031005] Published Tue Jul 14, 2015

We exploit the near field enhancement of nanoantennas to investigate the Raman spectra of otherwise not optically detectable carbon nanotubes (CNTs). We demonstrate that a top-down fabrication approach is particularly promising when applied to CNTs, owing to the sharp dependence of the scattered int…

[Phys. Rev. B 91, 235449] Published Mon Jun 29, 2015

We investigate the effect of parity-time (PT) symmetric optical potentials on the radiation of achiral and chiral dipole sources. Two properties unique to PT-symmetric potentials are observed. First, the dipole can be tuned to behave as a strong optical emitter or absorber based on the non-Hermitici…

[Phys. Rev. B 91, 245108] Published Fri Jun 05, 2015

Electromagnetic scattering has applications in astrophysics, atmospheric science, and medical imaging. Researchers design a metamaterial that exhibits anomalously weak scattering over a band of optical frequencies.

[Phys. Rev. X 5, 021021] Published Fri May 29, 2015

Quantum dots embedded in photonics nanostructures provide unprecedented control over the interaction between light and matter. This review gives an overview of the theoretical principles involved, as well as applications ranging from high-precision quantum electrodynamics experiments to quantum-information processing.

[Rev. Mod. Phys. 87, 347] Published Mon May 11, 2015

The discovery of light emission from metal-insulator-metal tunnel junctions in the 1970s suggested a low-energy, broadband source of visible light. Presently this technology is also of interest for generating subwavelength surface plasmons electrically. The authors show that inelastic electron tunneling excitation is potentially 10${}^5$ times as efficient for producing mid-infrared plasmons in graphene than in metal, offering great promise for on-chip integrated nanophotonics.

[Phys. Rev. Applied 3, 054001] Published Fri May 08, 2015

Hybrid nanostructures composed of both typical atoms and metallic nanoparticles such as nanoresonators host a variety of optical properties. Analytical modeling is used to derive the optical responses of such materials in a computationally feasible way.

[Phys. Rev. X 5, 021008] Published Fri Apr 17, 2015

[Phys. Rev. B 91, 159904] Published Mon Apr 13, 2015

We present evidence for “image biexcitons” within organic-inorganic perovskite-coated silver gratings. These composite quasiparticles are formed by the interaction between an exciton and its image in the metal mirror below, with binding energy 100 meV at room temperature. By changing the polar and a…

[Phys. Rev. B 91, 161303(R)] Published Fri Apr 10, 2015

We present a general method for retrieving the effective tensorial permittivity of uniaxially anisotropic metamaterials. By relaxing the usually imposed constraint of assuming nonmagnetic metal/dielectric metamaterials, we also retrieve the effective permeability tensor and show that multilayer hype…

[Phys. Rev. B 91, 155406] Published Tue Apr 07, 2015

We demonstrate the photogeneration of loaded dipole plasmonic antennas resonating at THz frequencies. This is achieved by the patterned optical illumination of a semiconductor surface using a spatial light modulator. Our experimental results indicate the existence of capacitive and inductive couplin…

[Phys. Rev. B 91, 125443] Published Tue Mar 31, 2015

Many biological structures, from macromolecules to proteins, as well as a number of solid-state systems including ferroelectric and ferro nano- and microstructures, possess static toroidal shapes. A theoretical study shows that the dynamic toroidal dipoles constructed from ionic crystals can be used to engineer metamaterials to control how electromagnetic radiation is scattered and transmitted.

[Phys. Rev. X 5, 011036] Published Fri Mar 27, 2015

In recent years we have learned to fabricate structures smaller than electromagnetic wavelengths, and to assemble them into metamaterials with exotic optical properties for previously unimaginable applications. One such property is perfect absorption of incident light, with no reflection or transmission, across many wavelengths. The authors review the physics, design principles, and classification of thin perfect absorbers, and outline avenues for progress.

[Phys. Rev. Applied 3, 037001] Published Tue Mar 17, 2015

A monolayer of graphene irradiated with circularly polarized light suggests a unique platform for surface electromagnetic wave (plasmon-polariton) manipulation. In fact, the time periodicity of the Hamiltonian leads to a geometric Aharonov-Anandan phase and results in a photovoltaic Hall effect in g…

[Phys. Rev. B 91, 075419] Published Wed Feb 18, 2015

Under certain conditions the spin of photons can acquire an unusual transverse component. Using intensity differences in the far-field, the transverse spin density is experimentally measured.

[Phys. Rev. Lett. 114, 063901] Published Mon Feb 09, 2015

We present a simple device architecture that allows all-electrical detection of plasmons in a graphene waveguide. The key principle of our electrical plasmon detection scheme is the nonlinear nature of the hydrodynamic equations of motion that describe transport in graphene at room temperature and i…

[Phys. Rev. B 91, 081402(R)] Published Thu Feb 05, 2015

A theoretical evaluation of the dynamic polarizability of graphene in a photoexcited carrier inversion state shows that graphene can support nonequilibrium plasmons with gain. The authors predict that the experimental observation of plasmon amplification in graphene is possible under realistic conditions. This would help overcome the barriers to using graphene in plasmonics due to plasmon losses.

[Phys. Rev. B 91, 075404] Published Tue Feb 03, 2015

In the context of plasmonic nanolasers, it has been previously recognized that systems with physically extended modes (as opposed to isolated cavity modes) can support lasing, and plasmonic crystals are a platform for such effects. In the present paper the authors present a general study that explores, from a unified perspective, the lasing properties of plasmonic crystals incorporating optically pumped four-level gain media.

[Phys. Rev. B 91, 041118(R)] Published Mon Jan 26, 2015

We develop a general quantum theory of the coupled plasmonic modes resulting from the near-field interaction between localized surface plasmons in a heterogeneous metallic nanoparticle dimer. In particular, we provide analytical expressions for the frequencies and decay rates of the bright and dark …

[Phys. Rev. B 91, 035431] Published Thu Jan 22, 2015

The acceleration of dense targets driven by the radiation pressure of high-intensity lasers leads to a Rayleigh-Taylor instability (RTI) with rippling of the interaction surface. Using a simple model it is shown that the self-consistent modulation of the radiation pressure caused by a sinusoidal rip…

[Phys. Rev. E 91, 013106] Published Wed Jan 21, 2015

We report on the observation of optical Stark effects in $J$-aggregate–metal hybrid nanostructures exhibiting strong exciton-surface-plasmon-polariton coupling. For redshifted nonresonant excitation, pump-probe spectra show short-lived dispersive line shapes of the exciton-surface-plasmon-polariton co…

[Phys. Rev. Lett. 114, 036802] Published Wed Jan 21, 2015

We investigate the tunable and switchable optical radiators and metamaterials formed by metallic nanodipole antennas with submicroscopic gaps (1.2 nm), of which linear and third-order nonlinear quantum conductivities are observed due to the photon-assisted tunneling effect. The quantum conductivitie…

[Phys. Rev. B 91, 035426] Published Tue Jan 20, 2015

We experimentally and theoretically demonstrate subwavelength scale localization of spoof surface plasmon polaritons at a point defect in a two-dimensional groove metal array. An analytical expression for dispersion relation of spoof surface plasmon polaritons substantiates the existence of a band g…

[Phys. Rev. B 91, 035116] Published Tue Jan 13, 2015

A numerically exact solution to the many emitter–cavity problem as an open many body system is presented. The solution gives access to the full, nonperturbative density matrix and thus the full quantum statistics and quantum correlations. The numerical effort scales with the third power in the numbe…

[Phys. Rev. B 91, 035306] Published Tue Jan 13, 2015

It is widely believed that surface plasmon polaritons (SPPs) at flat metal surfaces cannot be directly excited by free-space lights due to momentum mismatch. Here we propose a way to resonantly excite SPPs by lights without using any coupler and propose a kind of surface-plasmon-resonance (SPR) syst…

[Phys. Rev. A 91, 013817] Published Fri Jan 09, 2015

We study a hybrid mode in a composite system consisting of a localized metal nanosphere on a subwavelength fiber. It is found that the hybrid mode resulting from coupling of the fiber propagating mode and the plasmonic resonance is promising for strongly enhanced interaction between light and matter…

[Phys. Rev. A 91, 013805] Published Mon Jan 05, 2015

Photocathodes are used as sources in advanced applications such as free-electron lasers, but future applications will require higher brightness than today’s technology can provide. By combining heat treatment with lithography, the authors produce self-assembled nanostructures amidst an array of nanoholes in gold film. These structures can be engineered to propagate surface plasmon eigenmodes that yield photoemission intensity ratios as high as 10${}^8$.

[Phys. Rev. Applied 2, 064012] Published Tue Dec 30, 2014

Nonlinear continuum generation from diffraction-limited hot spots in rough silver films exhibits striking narrow-band intensity resonances in excitation wavelength. Time-domain Fourier spectroscopy uncovers how these resonances arise due to the formation of a “plasmon staircase”, a discreteness in t…

[Phys. Rev. Lett. 113, 266805] Published Tue Dec 30, 2014

The interactions between plasmonic and photonic modes of a cavity-coupled plasmonic crystal are studied in diffraction and diffractionless regimes, which lead us to the understanding of coherent interactions between electron plasma, higher order cavity, and diffraction modes. The strong interaction …

[Phys. Rev. Lett. 113, 263902] Published Mon Dec 29, 2014

Using exotic subwavelength structures to conceal objects has generated sensational articles about “invisibility cloaks”, but there are more subtle applications as well. This study extends one cloaking technique from the usual free-space geometries to the guided-wave structures of optical communications circuitry. Nanoprobes in the light path of an integrated plasmonic circuit can be efficiently hidden, and although the cloaked objects do not disturb the flow of light, they nevertheless do interact with it. This permits the probes to exchange information with the outside world, and so cunningly these “invisibility cloaks” can be exploited to produce signal antennas or detectors.

[Phys. Rev. Applied 2, 064009] Published Tue Dec 23, 2014

We have studied the amplified emission properties of nanoislands with CdSe quantum dots in ZnSe/CdSe/ZnSe heterostructures surrounded by metallic antennas. It has been found that variations of the optical antenna length give rise to periodic amplification of the integral emission intensity. The peri…

[Phys. Rev. B 90, 235313] Published Thu Dec 18, 2014

Surfaces that offer arbitrary control of reflected light have enormous implications in the field of nanophotonics. New metasurfaces consisting of gold nanorods are used to fully control the reflective properties of electromagnetic radiation.

[Phys. Rev. X 4, 041042] Published Tue Dec 09, 2014

We investigate a periodic array of aluminum nanoantennas embedded in a light-emitting slab waveguide. By varying the waveguide thickness, we demonstrate the transition from weak to strong coupling between localized surface plasmons in the nanoantennas and refractive index guided modes in the wavegui…

[Phys. Rev. B 90, 235406] Published Tue Dec 02, 2014

Besides the two fundamental symmetric and antisymmetric modes, a thin metal slab surrounded by a dielectric medium supports an infinite number of other modes whose propagation distances, however, are extremely short. We show that such a higher-order mode, normally not regarded to be useful, can turn…

[Phys. Rev. A 90, 053849] Published Wed Nov 26, 2014

We report a determination of the complex in-plane dielectric function of monolayers of four transition-metal dichalcogenides: $\mathrm{Mo}{\mathrm{S}}_2$, $\mathrm{Mo}\mathrm{S}{\mathrm{e}}_2$, $\mathrm{W}{\mathrm{S}}_2$, and $\mathrm{WS}{\mathrm{e}}_2$, for photon energies from 1.5 to 3 eV. The results were obtained from reflection spectra using a Kramers-Kronig constrained variational analysis. F…

[Phys. Rev. B 90, 205422] Published Mon Nov 17, 2014

It is known that $\epsilon$-near-zero (ENZ) structures may provide exciting possibilities for light-matter interaction, including the phenomenon of supercoupling, i.e., channeling of wave energy through ultranarrow conduits connecting two waveguides. Here, we extend this concept to the surface waves using st…

[Phys. Rev. B 90, 201107(R)] Published Thu Nov 13, 2014

The optical response of heterogeneous plasmonic trimer structures composed of a silver nanoparticle dimer and a central gold nanoparticle is investigated analytically and numerically. The plasmon resonance of the silver dimer is controlled through near-field coupling, resulting in plasmon resonance …

[Phys. Rev. B 90, 205414] Published Tue Nov 11, 2014

As one emerging plasmonic material, graphene can support surface plasmons at infrared and terahertz frequencies with unprecedented properties due to the strong interactions between graphene and low-frequency photons. Since graphene surface plasmons exist in the infrared and terahertz regime, they ca…

[Phys. Rev. B 90, 195411] Published Mon Nov 10, 2014

The authors present an effective-medium theory of the optical diamagnetic response of very dilute metal colloids. These dispersions of ferromagnetic metal clusters in diamagnetic hosts show a large, linear response under an applied magnetic field, which is of interest for emerging applications in sensing, integrated optical communications, and magneto-optical current transformers and transducers. This theory could be further extended to describe e.g., metal inclusions in polymers or glasses.

[Phys. Rev. Applied 2, 054003] Published Wed Nov 05, 2014

We study arrays of plasmonic nanoparticles combined with quantum emitters, quantum plasmonic lattices, as a platform for room-temperature studies of quantum many-body physics. We outline a theory to describe surface plasmon-polariton distributions when they are coupled to externally pumped molecules…

[Phys. Rev. A 90, 053604] Published Wed Nov 05, 2014

Planar metallic nanoparticles separated by nanoscale distances from a metal film support unique plasmonic resonances useful for controlling a wide range of photodynamic processes. The fundamental resonance of a film-coupled planar nanoparticle arises from a transmission-line mode localized between n…

[Phys. Rev. B 90, 195402] Published Mon Nov 03, 2014

Using ab initio calculations we predict the existence of one-dimensional (1D), atomically confined plasmons at the edges of a zigzag ${\mathrm{MoS}}_2$ nanoribbon. The strongest plasmon originates from a metallic edge state localized on the sulfur dimers decorating the Mo edge of the ribbon. A detailed analysis o…

[Phys. Rev. B 90, 161410(R)] Published Wed Oct 29, 2014

This paper reports a comprehensive experimental study of silver and gold plasmonic crystal lasers. Such periodic plasmon particle systems have recently triggered large attention due to the fact that localized plasmons and collective lattice resonances conspire to give large light-matter interaction strength in narrow resonances. The authors provide a detailed report on the conditions required for lasing, and a complete analysis of the underlying plasmonic lattice band structure.

[Phys. Rev. B 90, 155452] Published Tue Oct 28, 2014

A design for a photonic crystal made with so-called hyperbolic metamaterials could provide unprecedented control of light waves confined to the surface.

[Phys. Rev. X 4, 041014] Published Mon Oct 27, 2014

We present an ab initio study of the hybridization of localized surface plasmons in a metal nanoparticle dimer. The atomic structure, which is often neglected in theoretical studies of quantum nanoplasmonics, has a strong impact on the optical absorption properties when subnanometric gaps between th…

[Phys. Rev. B 90, 161407(R)] Published Fri Oct 24, 2014

Recent experimental studies on graphene on hexagonal boron nitride (hBN) have demonstrated that hBN is not only a passive substrate that ensures superb electronic properties of graphene's carriers, but that it actively modifies their massless Dirac fermion character through a periodic moiré potentia…

[Phys. Rev. B 90, 161406(R)] Published Thu Oct 23, 2014

We suggest a novel approach for generating the second-harmonic radiation in subwavelength graphene waveguides. We demonstrate that the quadratic phase matching between plasmonic guided modes of different symmetries can be achieved in a planar double-layer graphene structure when conductivity of one …

[Phys. Rev. B 90, 165433] Published Thu Oct 23, 2014

We theoretically investigate mode broadening of a high-$Q$ optical whispering-gallery microcavity coupled to a single or multiple dielectric or plasmonic subwavelength particles. The result shows that backscattering contributes dominantly to the mode broadening in both transmission and reflection spec…

[Phys. Rev. A 90, 043847] Published Tue Oct 21, 2014

A light-matter interaction modified by the material environment is one of the central topics in quantum electrodynamics. While a strong coupling between a single emitter and a cavity and the Markovian (exponential) relaxation regime are most straightforwardly covered by theory, real physical systems…

[Phys. Rev. A 90, 043836] Published Mon Oct 20, 2014

We theoretically investigate general existence conditions for broadband bulk large-wave-vector (high-$k)$ propagating waves (such as volume plasmon polaritons in hyperbolic metamaterials) in subwavelength periodic multilayer structures. Describing the elementary excitation in the unit cell of the stru…

[Phys. Rev. B 90, 155429] Published Thu Oct 16, 2014

We introduce two types of toroidal metamaterials which are invisible to surface plasmon polaritons (SPPs) propagating on a metal surface. The former is a toroidal handlebody bridging remote holes on the metal surface: It works as a kind of plasmonic counterpart of electromagnetic wormholes. The latt…

[Phys. Rev. A 90, 043812] Published Fri Oct 10, 2014