Observation of surface-plasmon phenomena that are dependent upon the handedness of the circularly polarized incident light (spin) is presented. The polarization-dependent near-field intensity distribution obtained in our experiment is attributed to the presence of a geometric phase arising from the interaction of light with an anisotropic and inhomogeneous nanoscale structure. A near-field vortex surface mode with a spin-dependent topological charge was obtained in a plasmonic microcavity. The remarkable phenomenon of polarization-sensitive focusing in a plasmonic structure was also demonstrated.
The guided dispersion characteristics of subwavelength nanoscale plasmonic coaxial lines are analyzed in detail over a wide optical frequency range below the plasma frequency with a varying gap between the inner and outer plasmonic conductors, providing important preliminary information for understanding the guided mode characteristics of subwavelength nanoscale coaxial lines with plasmonic metals. In particular, when the inner or outer radius is varied, guided modes with similar and dissimilar dispersive features are obtained and discussed. A brief comparison of the propagating modes for the …
The research area of plasmonics promises devices with ultrasmall footprint operating at ultrafast speeds and with lower energy consumption compared to conventional electronics. These devices will operate with light and bridge the gap between microscale dielectric photonic systems and nanoscale electronics. Recent research advancements in nanotechnology and optics have led to the creation of a plethora of new plasmonic designs. Among the most promising are nanoscale antennas operating at optical frequencies, called nanoantennas. Plasmonic nanoantennas can provide enhanced and controllable light…
Focusing electromagnetic energy to sub-wavelength dimensions has become an increasingly active field of research for a variety of applications such as Heat Assisted Magnetic Recording (HAMR), nanolithography, and nanoscale optical characterization of biological cells and single molecules using near-field scanning optical microscopy (NSOM) technique. Double-sided surface plasmons in a metal-insulator-metal (MIM) geometry have been shown to have very small wavelengths for dielectric of thickness of less than 10 nm. A tapered dielectric structure sandwiched between metal, can be used to efficient…
The emerging field of plasmonics can lead to enhanced light matter interactions at extremely nanoscale regions. Plasmonic (metallic) devices promise to efficiently control both classical and quantum properties of light. Plasmonic waveguides are usually used to excite confined electromagnetic modes at the nanoscale that can strongly interact with matter. The analysis of these nanowaveguides exhibits similarities with their low frequency microwave counterparts. In this article, we review ways to study plasmonic nanostructures coupled to quantum optical emitters from a classical electromagnetic p…
To enable multiple functions of plasmonic nanocircuits, it is of key importance to control the propagation properties and the modal distribution of the guided optical modes such that their impedance matches to that of nearby quantum systems and desired light-matter interaction can be achieved. Here, we present efficient mode converters for manipulating guided modes on a plasmonic two-wire transmission line. The mode conversion is achieved through varying the path length, wire cross section and the surrounding index of refraction. Instead of pure optical interference, strong near-field coupling…
While the thermal and electromagnetic properties of plasmonic nanostructures are well understood, nanoscale thermometry still presents an experimental and theoretical challenge. Plasmonic structures can confine electromagnetic energy at the nanoscale, resulting in local, inhomogeneous, controllable heating. But reading out the temperature with nanoscale precision using optical techniques poses a difficult challenge. Here we report on the optical thermometry of individual gold nanorod trimers that exhibit multiple wavelength-dependent plasmon modes resulting in measurably different local temper…
Integration of photon pairs nanosources is a major challenge for quantum technology. In this context, we develop a formalism for the investigation of Spontaneous Parametric Down Conversion in hybrid structures that combine plasmonic resonances and intrinsic nonlinearity. Using quantum and numerical approaches together, we quantitatively evaluate photon pair correlation measurements for realistic experimental configurations. Hybrid structures embedding a small nanocystal allow for a $10^{3}$ fold increase in pair production compared to the same nanocrystal alone and a photon pair production eff…
Here, we propose a conceptual approach for design of an ultracompact nanoscale passive optical circulator based on the excitation of plasmonic resonances. We study a three-port Y-junction with a deep subwavelength plasmonic nanorod structure integrated into its core. We show theoretically that such a structure immersed in the magneto-optical media may function as magnetically tunable scatterer tilting and rotating its near-field distribution and corresponding radiation. We demonstrate, using numerical simulations, that such a rotation of the near-field radiation yields a break in the symmetry …
Nanotechnology and the consequent emergence of miniaturized devices are driving the need to improve our understanding of the mechanical properties of a myriad of materials. Here we focus on amorphous polymeric materials and introduce a new way to determine the nanoscale mechanical response of polymeric thin films in the GHz range, using ultrafast optical means. Coupling of the films to plasmonic nanoantennas excited at their vibrational eigenfrequencies allows the extraction of the values of the mechanical moduli as well as the estimation of the glass transition temperature via time-domain mea…
Open quantum systems consisting of coupled bound and continuum states have been studied in a variety of physical systems, particularly within the scope of nuclear, atomic and molecular physics. In the open systems, the effects of the continuum decay channels are accounted for by indirect non-Hermitian couplings among the quasi-bound states. Here we explore anti-Hermitian coupling in a plasmonic system for spatially manipulating light on the nano-scale. We show that by utilizing the anti-Hermitian coupling, plasmonic antennas closely packed within only λ/15 separations can be individually excit…
We have investigated second harmonic generation (SHG) from Ag-coated LiNbO3 (LN) core-shell nanocuboids and found that giant SHG can occur via deliberately designed double plasmonic resonances. By controlling the aspect ratio, we can tune fundamental wave (FW) and SHG signal to match the longitudinal and transverse plasmonic modes simultaneously, and achieve giant enhancement of SHG by more than five orders of magnitude in comparison to a bare LN nanocuboid and by about one order of magnitude to the case adopting only single plasmonic resonance. The underlying key physics is that the double-re…
The search for miniaturized components for nonlinear optical processes needs a way to overcome the efficiency loss due to the effective size reduction of the active medium. We investigate here a combination of a nanosized nonlinear dielectric crystal and metallic nanoantennas that benefits from both the intrinsic nonlinear conversion efficiency of the nonlinear medium and the local-field enhancement of plasmonic resonances in metallic nanostructures. Careful comparison between experiments and numerical simulations reveals that the observed 10 to 1000 fold enhancement in Second Harmonic Generat…
We theoretically investigate a nanoscale mode-division multiplexing scheme based on parity-time (PT) symmetric coaxial plasmonic waveguides. Coaxial waveguides support paired degenerate modes corresponding to distinct orbital angular momentum states. PT symmetric inclusions of gain and loss break the degeneracy of the paired modes and create new hybrid modes without orbital angular momentum. This process can be made thresholdless by matching the mode order with the number of gain and loss sections within the coaxial ring. Using both a Hamiltonian formulation and degenerate perturbation theory,…
We develop a self-consistent finite element method to study spontaneous emission at nanoscale proximity of plasmonic waveguides. In the model, it is assumed that only one guided mode is dominatingly excited by the quantum emitter. With such one dominating mode assumption, the cross section of the plasmonic waveguide can be arbitrary. We apply our numerical method to calculate the coupling of a quantum emitter to a cylindrical nanowire and a rectangular waveguide, and compare the cylindrical nanowire to previous work valid in quasistatic approximation. The fraction of the energy coupled to the …
Spin defects in hexagonal boron nitride, and specifically the negatively charged boron vacancy (VB) centres, are emerging candidates for quantum sensing. However, the VB defects suffer from low quantum efficiency and as a result exhibit weak photoluminescence. In this work, we demonstrate a scalable approach to dramatically enhance the VB- emission by coupling to a plasmonic gap cavity. The plasmonic cavity is composed of a flat gold surface and a silver cube, with few-layer hBN flakes positioned in between. Employing these plasmonic cavities, we extracted two orders of magnitude in photolumin…
Fabricating nanocavities in which optically-active single quantum emitters are precisely positioned, is crucial for building nanophotonic devices. Here we show that self-assembly based on robust DNA-origami constructs can precisely position single molecules laterally within sub-5nm gaps between plasmonic substrates that support intense optical confinement. By placing single-molecules at the center of a nanocavity, we show modification of the plasmon cavity resonance before and after bleaching the chromophore, and obtain enhancements of $\geq4\times10^3$ with high quantum yield ($\geq50$%). By …
Coherent broadband excitation of plasmons brings ultrafast photonics to the nanoscale. However, to fully leverage this potential for ultrafast nanophotonic applications, the capacity to engineer and control the ultrafast response of a plasmonic system at will is crucial. Here, we develop a framework for systematic control and measurement of ultrafast dynamics of near-field hotspots. We show deterministic design of the coherent response of plasmonic antennas at femtosecond timescales. Exploiting the emerging properties of coupled antenna configurations, we use the calibrated antennas to enginee…
This chapter discusses a hydrodynamics-inspired approach to trap and manipulate light in plasmonic nanostructures, which is based on steering optical powerflow around nano-obstacles. New insights into plasmonic nanofocusing mechanisms are obtained by invoking an analogy of the 'photon fluid' (PF). By proper nanostructure design, PF kinetic energy can be locally increased via convective acceleration and then converted into 'pressure' energy to generate localized areas of high field intensity. In particular, trapped light can be molded into optical vortices -tornado-like areas of circular motion…
We theoretically investigate several types of plasmonic slot waveguides for enhancing the measured signal in Raman spectroscopy, which is a consequence of electric field and Purcell factor enhancements, as well as an increase in light-matter interaction volume and the Raman signal collection efficiency. An intuitive methodology is presented for calculating the accumulated Raman enhancement factor of an ensemble of molecules in waveguide sensing, which exploits an analytical photon Green function expansion in terms of the waveguide normal modes, and we combine this with a quantum optics formali…
Noble metal nanoparticles show specific optical properties due to the excitation of localized surface plasmons that make them attractive candidates for highly sensitive bionanosensors. The underlying physical principle is either an analyte-induced modification of the dielectric properties of the medium surrounding the nanoparticle or an increase of the excitation and emission rates of an optically active analyte by the resonantly enhanced plasmon field. Either way, besides the nanoparticle geometry the dielectric properties of the metal and nanoscale surface roughness play an important role fo…
We propose a scheme to realize nonlinear coherent perfect absorption (CPA) at the nanoscale using epsilon-near-zero (ENZ) plasmonic waveguides. The general conditions to achieve CPA in a linear ENZ plasmonic waveguide are analyzed and presented. The proposed ENZ waveguides support an effective ENZ response at their cut-off frequency, where the CPA effect occurs under the illumination of two counter-propagating plane waves with equal amplitudes and appropriate phase distributions. In addition, the strong and uniform field enhancement inside the nanochannels of the waveguides at the ENZ resonanc…
Plasmonic wireless nanolinks hold great promise to overcome limitations from conventional metallic wires, namely narrow bandwidths, Ohmic losses, dispersion and cross-talking. However, current developments are limited to the wireless communication between two fixed points, i.e., a fixed transmitter with a fixed receiver, which in turn limits the energy efficiency and integration levels. In this work, we propose the use of magnetic fields for active tuning of the radiation beam steering of plasmonic nanoantennas. The physical principle behind our concept is shown with rigorous solution of the r…
Electrically-driven optical antennas can serve as compact sources of electromagnetic radiation operating at optical frequencies. In the most widely explored configurations, the radiation is generated by electrons tunneling between metallic parts of the structure when a bias voltage is applied across the tunneling gap. Rather than relying on an inherently inefficient inelastic light emission in the gap, we suggest to use a ballistic nanoconstriction as the feed element of an optical antenna supporting plasmonic modes. We discuss the underlying mechanisms responsible for the optical emission, an…
Nanoscale localization of electromagnetic fields near metallic nanostructures underpins the fundamentals and applications of plasmonics. The unavoidable energy loss from plasmon decay, initially seen as a detriment, has now expanded the scope of plasmonic applications to exploit the generated hot carriers. However, quantitative understanding of the spatial localization of these hot carriers, akin to electromagnetic near-field maps, has been elusive. Here we spatially map hot-electron-driven reduction chemistry with 15 nanometre resolution as a function of time and electromagnetic field polariz…
Simultaneous spatio-temporal confinement of energetic electron pulses to femtosecond and nanometer scales is a topic of great interest in the scientific community, given the potential impact of such development on a wide spectrum of scientific and industrial applications. For example, in ultrafast electron scattering, nanoscale probes would enable accurate maps of structural dynamics in materials with nanoscale heterogeneity, thereby understanding the role of boundaries and defects on macroscopic properties. On the other hand, advances in this field are mostly limited by the electron source br…
We demonstrate spatially-resolved measurements of spontaneous and stimulated electron-photon interactions in nanoscale optical near fields using electron energy-loss spectroscopy (EELS), cathodoluminescence spectroscopy (CL), and photon-induced near-field electron microscopy (PINEM). Specifically, we study resonant surface plasmon modes that are tightly confined to the tip apexes of an Au nanostar, enabling a direct correlation of EELS, CL, and PINEM on the same physical structure at the nanometer length scale. Complemented by numerical electromagnetic boundary-element method calculations, we …
Evanescent light can be localized at the nanoscale by resonant absorption in a plasmonic nanoparticle or taper or by transmission through a nanohole. However, a conventional lens cannot focus free-space light beyond half of the wavelength λ. Nevertheless, precisely tailored interference of multiple waves can form a hotspot in free space of arbitrarily small size known as superoscillation. Here, we report a new type of integrated metamaterial interferometry that allows for the first time mapping of fields with deep subwavelength resolution ~ λ/100. It reveals that electromagnetic field near the…
Surface-plasmon-polariton waves propagating at the interface between a metal and a dielectric, hold the key to future high-bandwidth, dense on-chip integrated logic circuits overcoming the diffraction limitation of photonics. While recent advances in plasmonic logic have witnessed the demonstration of basic and universal logic gates, these CMOS oriented digital logic gates cannot fully utilize the expressive power of this novel technology. Here, we aim at unraveling the true potential of plasmonics by exploiting an enhanced native functionality - the majority voter. Contrary to the state-of-th…
Room-temperature strong coupling between plasmonic nanocavities and monolayer semiconductors is a prominent path towards efficient, integrated light-matter interactions. However, designing such systems is challenging due to the nontrivial dependence of the strong coupling on various properties of the cavity and emitter, as well as the subwavelength scale of the interaction. In this work, we develop a methodology for obtaining hybrid nanostructures consisting of plasmonic metasurfaces coupled to atomically thin WS2 layers, exhibiting extreme values of Rabi splitting, by inverse design of the ne…
Efficient delivery of light into nanoscale volumes by converting free photons into localized charge-density oscillations (surface plasmons) enables technological innovation in various fields from biosensing to photovoltaics and quantum computing. Conventional plasmonic nanostructures are designed as nanoscale analogs of radioantennas and waveguides. Here, we discuss an alternative approach for plasmonic nanocircuit engineering that is based on molding the optical powerflow through 'vortex nanogears' around a landscape of local phase singularities 'pinned' to plasmonic nanostructures. We show t…
The emergence of two-dimensional transition metal chalcogenide materials has sparked an intense activity in valleytronics since their valley information can be directly encoded and detected by using the spin angular momentum of light. For their practical applications such as on-chip valley logic gates and chip-to-chip valley transport, the encoding and processing of valley pseudospin using light should be extended to an integrated, on-chip nanophotonic system. Here, we successfully demonstrate, at room temperature, the valley-dependent directional coupling of light using a plasmonic nanowire-W…
We theoretically explore the notion of nonreciprocal near-zone manipulation of electromagnetic fields within subwavelength plasmonic nanostructures embedded in magneto-optical materials. We derive an analytical model predicting a strong, magneto-optically induced time-reversal symmetry breaking of localized plasmonic resonances in topologically symmetric structures. Our numerical simulations of plasmon excitations reveal a considerable near-zone power flow rotation within such hybrid nanostructures, demonstrating nanoscale nonreciprocity. This can be considered as another mechanism for tuning …
Optical beams carrying orbital angular momentum (OAM) can find tremendous applications in several fields. In order to apply these particular beams in photonic integrated devices innovative optical elements have been proposed. Here we are interested in the generation of OAM-carrying beams at the nanoscale level. We design and experimentally demonstrate a plasmonic optical vortex emitter, based on a metal-insulator-metal holey plasmonic vortex lens. Our plasmonic element is shown to convert impinging circularly polarized light to an orbital angular momentum state capable of propagating to the fa…
Recent experiments showed that unity-order index change in a transparent conducting oxide (TCO) can be achieved in a metal-oxide-semiconductor (MOS) structure by accumulation charge. However, the ultrathin (~5nm) accumulation layer and inherent absorption of TCOs impede the practical applications of this effect. Herein, we propose and explore a novel waveguide, namely "TCO-slot waveguide", which combines both the tunable property of a TCO and field enhancement of a slot waveguide. In particular, light absorption can be sharply enhanced when the slot dielectric constant is tuned close to zero. …
Optical computing uses photons as information carriers, opening up the possibility for ultrahigh-speed and ultrawide-band information processing. Integrated all-optical logic devices are indispensible core components of optical computing systems. However, up to now, little experimental progress has been made in nanoscale all-optical logic discriminators, which have the function of discriminating and encoding incident light signals according to wavelength. Here, we report a strategy to realize a nanoscale all-optical logic discriminator based on plasmonic bandgap engineering in a planar plasmon…
Photonic quantum technologies have been extensively studied in quantum information science, owing to the high-speed transmission and outstanding low-noise properties of photons. However, applications based on photonic entanglement are restricted due to the diffraction limit. In this work, we demonstrate for the first time the maintaining of quantum polarization entanglement in a nanoscale hybrid plasmonic waveguide composed of a fiber taper and a silver nanowire. The transmitted state throughout the waveguide has a fidelity of 0.932 with the maximally polarization entangled state Φ+. Furthermo…
Nanoscale pulsed light is highly desirable in nano-integrated optics. In this letter, we obtained femtosecond pulses with THz repetition frequency via the strong coupling between quantum emitters (QEs) and plasmonic resonators. Our structure consists of a V-groove (VG) plasmonic resonator and a nanowire embedded with two-level QEs. The influences of the incident light intensity and QE number density on the transmission response for this hybrid system are investigated through semi-classical theory and simulation. It is found that the transmission response can be modulated to the pulse form. The…
Nowadays, via controlling surface plasmons (SPs) on elaborate man-made structures, plasmonics aiming at manipulating light beyond the diffraction limit has aroused great interest. Here, nevertheless, we demonstrate in short-pulse laser ablation ultrafast active plasmonic structures spontaneously generate in virtue of plasmonic effects rather than human ingenuity. First, the splitting of laser-induced subwavelength gratings that is experimentally evidenced on ZnO, Si, and GaAs, is confirmed to originate in the conversion of SP modes from the resonant to the nonresonant mode and further to the i…
All-optical switching (AOS) of magnetic domains by femtosecond laser pulses was first observed in the transition metal-rare earth (TM-RE) alloy GdFeCo1-5; this phenomenon demonstrated the potential for optical control of magnetism for the development of ever faster future magnetic recording technologies. The technological potential of AOS has recently increased due to the discovery of the same effect in other materials, including RE-free magnetic multilayers6,7. However, to be technologically meaningful, AOS must compete with the bit densities of conventional storage devices, restricting optic…
Nonreciprocity is important for optical information processing, full-duplex communications, and protection of sensitive laser equipment from unwanted reflections. However, it is very challenging to obtain strong nonreciprocal response in optical frequencies, especially when nanoscale configurations are considered. In this work, we solve this problem by demonstrating a compact bifacial plasmonic metasurface that acts as a new ultrathin nonreciprocal transmission filter at near-infrared frequencies. The proposed nanostructure is simple to be practically implemented, since it is composed of two s…
Plasmonic enhancement of nonlinear optical processes confront severe limitations arising from the strong dispersion of metal susceptibilities and small interaction volumes that hamper desirable phase-matching-like conditions. Maximizing nonlinear interactions in nanoscale systems require simultaneous excitation of resonant modes that spatially and constructively overlap at all wavelengths involved in the process. Here, we present a hybrid rectangular patch antenna design for optimal second harmonic generation (SHG) that is characterized by a non-centrosymmetric dielectric/ferroelectric materia…
Boosting nonlinear frequency conversion in extremely confined volumes remains a key challenge in nano-optics, nanomedicine, photocatalysis, and background-free biosensing. To this aim, field enhancements in plasmonic nanostructures are often exploited to effectively compensate for the lack of phase-matching at the nanoscale. Second harmonic generation (SHG) is, however, strongly quenched by the high degree of symmetry in plasmonic materials at the atomic scale and in nanoantenna designs. Here, we devise a plasmonic nanoantenna lacking axial symmetry, which exhibits spatial and frequency mode o…
Single molecule detection has revolutionised the fields of chemistry and biology by offering powerful ways to study individual molecules under different scenarios. Nanophotonic structures, including plasmonic antennas, significantly overcome the concentration limit at which single molecule events can be observed, enabling their detection at concentrations that are relevant to biological and chemical processes. Although antennas can be fabricated in large arrays, probing dynamic events requires high temporal resolution, which is best achieved by serial antenna interrogation. Unfortunately, this…
Many consumer technologies and scientific methods rely on photodetection of infrared light. We report a Schottky photodetector operating below silicon's band gap energy, through hot carrier injection from a nanoscale metallic absorber. Our design relies on simple CMOS-compatible 'bottom up' fabrication of fractally nanostructured aluminium films. Due to the fractal nature of the nanostructuring, the aluminium films support plasmonically enhanced absorption over a wide wavelength range. We demonstrate two orders of magnitude improvements of responsivity, noise-equivalent-power, and detectivity …
Recently, the implementation of plasmonic nanoantennas has opened new possibilities to investigate the nanoscale dynamics of individual biomolecules in living cell. However, studies have yet been restricted to single molecular species as the narrow wavelength resonance of gold-based nanostructures precludes the simultaneous interrogation of different fluorescently labeled molecules. Here we exploited broadband aluminum-based nanoantennas carved at the apex of near-field probes to resolve nanoscale-dynamic molecular interactions on intact living cell membranes. Through multicolor excitation, we…
Strong-field photoemission from metal nanostructures enabled fundamental discoveries recently. Here, we deliver theoretical demonstration of the electric field control of electrons in the closest nanoscale vicinity of plasmonic nanoparticles with the help of few-cycle laser waveforms. We analyze the effect of plasmonic resonance on photoemission properties and show that it is only off-resonant nanoparticles that can provide electron control on a true sub-fs timescale.
A type of Tamm states inside metal-insulator-metal (MIM) waveguides is proposed. An impedance based transfer matrix method is adopted to study and optimize it. With the participation of the plasmonic Tamm states, fields could be enhanced twice: the ffirst is due to the coupling between a normal waveguide and a nanoscaled plasmonic waveguide and the second is due to the strong localization and field enhancement of Tamm states. As shown in our 2D coupling configuration, |E|^2 is enhanced up to 1050 times when 1550 nm light is coupled from an 300 nm Si slab waveguide into an 40 nm MIM waveguide.
Nanophotonic devices take advantage of geometry-dependent optical properties to confine and enhance the interaction of light with matter on small scales. By carefully patterning nanoscale geometries, coupling of responses across distinct physical domains can be achieved, such as photon and phonon modes in optomechanical crystals. Extreme optical confinement of plasmonics can localize strong cross-domain interactions into nanometer-scale volumes, smaller than many nanosystem's thermal and mechanical eigenmodes, opening new regimes for engineering reconfigurable, dynamic nanosystems. Here, we pr…
Bidirectional nanoantennas are of key relevance for advanced functionalities to be implemented at the nanoscale, and in particular for color routing in an ultracompact flat-optics configuration. Here we demonstrate a novel approach avoiding complex collective geometries and/or restrictive morphological parameters, based on cross-polarized detuned plasmonic nanoantennas in a uniaxial (quasi-1D) bimetallic configuration. The nanofabrication of such a flat-optics system is controlled over a large-area (cm^2) by a novel self-organized technique exploiting ion-induced nanoscale wrinkling instabilit…
Experimental approaches to manipulate light-matter interaction at nanoscale have quickly advanced in recent years, leading to the demonstration of spaser (surface plasmon amplification by stimulated emission of radiation) in plasmonic nanocavities. Yet, a well-understood analytical theory to better understand and quantitatively explain the connotation of spaser system is urgently needed. Here we develop an all-analytical semiclassical theory to investigate the energy exchange between active materials and fields and the spaser performance in a plasmonic nanocavity. The theory can be commonly us…
The nanoscale interaction between single emitters and plasmonic structures is traditionally studied by relying on near-perfect, deterministic, nanoscale-control. This approach is ultra-low throughput thus rendering systematic studies difficult to impossible. Here, we show that super resolution microscopy in combination with data-driven statistical analysis allows studying near-field interactions of single molecules with resonant nanoantennas. We systematically tune the antennas' spectral resonances and show that emitters can be separated according to their coupling strength with said structure…
Research on graphene has revealed its unique optical properties, including strong coupling with light, high-speed operation, and gate-variable optical conductivity, which promise to satisfy the needs of future electro-optic (EO) modulators. In particular, recent work demonstrated a broadband EO modulator based on the interband absorption of graphene with overall length only 40μm. However, compared with the size of on-chip electronic components it is still bulky. On-chip optical interconnects require EO modulation at the nanoscale. The key to achieve nanoscale graphene EO modulation is to great…
Plasmonic waveguides are key elements in nanophotonic devices serving as optical interconnects between nanoscale light sources and detectors. Multimode operation in plasmonic two-wire transmission lines promises important degrees of freedom for near-field manipulation and information encoding. However, highly confined plasmon propagation in gold nanostructures is typically limited to the near-infrared region due to ohmic losses, excluding all visible quantum emitters from plasmonic circuitry. Here, we report on top-down fabrication of complex plasmonic nanostructures in single-crystalline silv…
