Negative friction refers to a frictional force that acts in the same direction as the motion of an object, which has been predicted in terahertz(THz) gain systems [Phys. Rev. B 108 045406(2023)]. In this work, we inve...Negative friction refers to a frictional force that acts in the same direction as the motion of an object, which has been predicted in terahertz(THz) gain systems [Phys. Rev. B 108 045406(2023)]. In this work, we investigate the enhancement of the negative friction experienced by nanospheres placed near a graphene substrate. We find that the magnitude of negative friction is related to the resonant coupling between the surface plasmon polaritons(SPPs) of the graphene and localized surface phonon polaritons(LSPh P) of nanospheres. We exam nanospheres consisted of several different materials, including SiO_(2), Si C, Zn Se, Na Cl, ln Sb. Our results suggest that the LSPh P of Na Cl nanospheres match effectively with the amplified SPPs of graphene sheets. The negative friction for Na Cl nanospheres can be enhanced about one-to-two orders of magnitude compared to that of silica(SiO_(2)) nanospheres. At the resonant peak of negative friction, the required quasi-Fermi energy of graphene is lower for Na Cl nanospheres. Our finds hold great prospects for the mechanical manipulations of nanoscale particles.展开更多
The rise of plasmonic metamaterials in recent years has unveiled the possibility of revolutionizing the entire field of optics and photonics, challenging well-established technological limitations and paving the way t...The rise of plasmonic metamaterials in recent years has unveiled the possibility of revolutionizing the entire field of optics and photonics, challenging well-established technological limitations and paving the way to innovations at an unprecedented level To capitalize the disruptive potential of this rising field of science and technology, it is important to be able to combine the richness of optical phenomena enabled by nanoplasmonics in order to realize metamaterial components, devices, and systems of increasing complexity. Here, we review a few recent research directions in the field of plasmonic metamaterials, which may foster further advancements in this research area. We will discuss the anomalous scattering features enabled by plasmonic nanoparticles and nanoclusters, and show how they may represent the fundamental building blocks of complex nanophotonic architectures. Building on these concepts, advanced components can be designed and operated, such as optical nanoantennas and nanoantenna arrays, which, in turn, may be at the basis of metasurface devices and complex systems. Following this path, from basic phenomena to advanced functionalities, the field of plasmonic metamaterials offers the promise of an important scientific and technological impact, with applications spanning from medical diagnostics to clean energy and information processing.展开更多
This paper presents a review of recent investigational studies on exciting Surface Plasmon Polaritous (SPPs)in MicroWave (MW)and TeraHertZ (THz)regimes by using subwavelength corrugated patterns on conductive or metal...This paper presents a review of recent investigational studies on exciting Surface Plasmon Polaritous (SPPs)in MicroWave (MW)and TeraHertZ (THz)regimes by using subwavelength corrugated patterns on conductive or metal surfaces.This article also describes SPP Microstrip (MS)structures at microwave and terahertz frequencies, and compares their significance with that of conventional MS Transmission Lines (TL),in order to tackle the key challenges of high gain,bandwidth size,compactness,TL losses,and signal integrity in high-end electronic de- vices.Because they have subwavelength properties,surface plasmon polaritous are gaining attention for their improved performance and ability for miniaturization in high-speed dense circuits.They possess comparably minuscule wavelength compared to incident light (photons).Consequently,they can demonstrate stronger spatial confinement and higher local field intensity at optical frequencies.In addition to engineering spoof SPP waveguides,which are created by engraving grooves and slits on metal surfaces to allow operation on at low frequencies (microwave and terahertz),semiconductors with smaller permittivity values and thus lower free charge carrier concentration have been demonstrated as a potential candidate in plasmonic devices.If necessary,further tuning of semiconductor-based SPP structures is aided by controlling the charge carrier concentration through doping,or by external stimuli such as optical illumination or thermal excitation of charge carriers from valence to conduction bands.This article conclusively covers previously elucidated perspectives on manipulating SSPPs in the MW and THz ranges,and emphasizes how these could steer next-generation plasmonic devices.展开更多
In this paper, a plasmonics refractive index sensor with the semiring-stub system coupled to a bus waveguide is proposed. The structure can achieve wavelength band tunable and ultra-sharp Fano resonance. The coupling ...In this paper, a plasmonics refractive index sensor with the semiring-stub system coupled to a bus waveguide is proposed. The structure can achieve wavelength band tunable and ultra-sharp Fano resonance. The coupling mechanism between the bright mode and dark mode is investigated in detail, and apparent plasmon induced transparency(PIT) is realized on the resonance wavelength. The full width at half maximum(FWHM) of the resonant wavelength is modulated by adjusting the coupled distance. The sensitivity and figure of merit(FOM) of the proposed sensor can reach up to 600 nm/RIU and 120 on the visible region, respectively, and this performance can be helpful for designing the photonic integrated circuit and optical communication, in addition, it can be applied for bio-sensing.展开更多
We discuss a new class of phenomena that we call ＂spin plasmonics＂. It is motivated by three different recent trends of physics research： （i） spintronics, （ii） plasmonics, and （iii） topological properties as ...We discuss a new class of phenomena that we call ＂spin plasmonics＂. It is motivated by three different recent trends of physics research： （i） spintronics, （ii） plasmonics, and （iii） topological properties as is exemplified by the quantized Hall effect. This involves the physics of the ＂magnetic surface plasmon＂ （MSP） which provides for an analog of the edge states discussed in the quantized Hall effect. Their properties can be easily tuned by an external magnetic field. They are coupled to the electromagnetic field and can be injected into metallic structures and induce spin and charge currents and hold the promise of miniturization of nonreciprocal devices.展开更多
Germanene nanostrips(GeNSs)have garnered significant attention in modern semiconductor technology due to their exceptional physical characteristics,positioning them as promising candidates for a wide range of applicat...Germanene nanostrips(GeNSs)have garnered significant attention in modern semiconductor technology due to their exceptional physical characteristics,positioning them as promising candidates for a wide range of applications.GeNSs exhibit a two-dimensional(buckled)honeycomb-like lattice,which is similar to germanene but with controllable bandgaps.The modeling of GeNSs is essential for developing appropriate synthesis methods as it enables understanding and controlling the growth process of these systems.Indeed,one can adjust the strip width,which in turn can tune the bandgap and plasmonic response of the material to meet specific device requirements.In this study,the objective is to investigate the electronic behav-ior and THz plasmon features of GeNSs(≥100 nm wide).A semi-analytical model based on the charge-carrier velocity of free-standing germanene is utilized for this purpose.The charge-carrier velocity of freestanding germanene is determined through the GW approximation(V_(F)=0.702×10^(6)m·s^(−1)).Within the width range of 100 to 500 nm,GeNSs exhibit narrow bandgaps,typi-cally measuring only a few meV.Specifically,upon analysis,it was found that the bandgaps of the investigated GeNSs ranged between 29 and 6 meV.As well,these nanostrips exhibit√q-like plasmon dispersions,with their connected plasmonic fre-quency(≤30 THz)capable of being manipulated by varying parameters such as strip width,excitation plasmon angle,and sam-ple quality.These manipulations can lead to frequency variations,either increasing or decreasing,as well as shifts towards larger momentum values.The outcomes of our study serve as a foundational motivation for future experiments,and further con-firmation is needed to validate the reported results.展开更多
Nano-optics is an emergent research field in physics that appeared in the 1980s,which deals with light–matter optical interactions at the nanometer scale.In early studies of nano-optics,the main concern focus is to o...Nano-optics is an emergent research field in physics that appeared in the 1980s,which deals with light–matter optical interactions at the nanometer scale.In early studies of nano-optics,the main concern focus is to obtain higher optical resolution over the diffraction limit.The researches of near-field imaging and spectroscopy based on scanning near-field optical microscopy(SNOM)are developed.The exploration of improving SNOM probe for near-field detection leads to the emergence of surface plasmons.In the sense of resolution and wider application,there has been a significant transition from seeking higher resolution microscopy to plasmonic near-field modulations in the nano-optics community during the nano-optic development.Nowadays,studies of nano-optics prefer the investigation of plasmonics in different material systems.In this article,the history of the development of near-field optics is briefly reviewed.The difficulties of conventional SNOM to achieve higher resolution are discussed.As an alternative solution,surface plasmons have shown the advantages of higher resolution,wider application,and flexible nano-optical modulation for new devices.The typical studies in different periods are introduced and characteristics of nano-optics in each stage are analyzed.In this way,the evolution progress from near-field optics to plasmonics of nano-optics research is presented.The future development of nano-optics is discussed then.展开更多
The surface plasmon polaritons of the topological insulator Bi2Se3 can be excited by using etched grating or grave structures to compensate the wave vector mismatch of the incident photon and plasmon. Here, we demonst...The surface plasmon polaritons of the topological insulator Bi2Se3 can be excited by using etched grating or grave structures to compensate the wave vector mismatch of the incident photon and plasmon. Here, we demonstrate novel gold grating/Bi2Se3 thin film/sapphire hybrid structures, which allow the excitation of surface plasmon polaritons propagating through nondestructive Bi2Se3 thin film with the help of gold diffractive gratings. Utilizing periodic Au surface structures,the momentum can be matched and the normal-incidence infrared reflectance spectra exhibit pronounced dips. When the width of the gold grating W(with a periodicity 2 W) increases from 400 nm to 1500 nm, the resonant frequencies are tuned from about 7000 cm-1 to 2500 cm-1. In contrast to the expected ■ dispersion for both massive and massless fermions,where q ~π/W is the wave vector, we observe a sound-like linear dispersion even at room temperature. This surface plasmon polaritons with linear dispersion are attributed to the unique noninvasive fabrication method and high mobility of topological surface electrons. This novel structure provides a promising application of Dirac plasmonics.展开更多
The plasmonics Talbot effect in metallic layer with infinite periodic grooves is presented in this study. Numerical approach based on the finite element method is employed to verify the derived Talbot carpet on the no...The plasmonics Talbot effect in metallic layer with infinite periodic grooves is presented in this study. Numerical approach based on the finite element method is employed to verify the derived Talbot carpet on the non-illumination side. The groove depth is less than the metallic layer thickness; however, for specific conditions, surface plasmons polaritons(SPPs)can penetrate through grooves, propagate under the metallic layer, and form Talbot revivals. The geometrical parameters are specified via groove width, gap size, period, and wavelength, and their proper values are determined by introducing two opening ratio parameters. To quantitatively compare different Talbot carpets, we introduce new parameters such as R-square that characterizes the periodicity of Talbot images. The higher the R-square of a carpet, the more coincident with non-paraxial approximation the Talbot distance becomes. We believe that our results can help to understand the nature of SPPs and also contribute to exploring this phenomenon in Talbot-image-based applications, including imaging, optical systems, and measurements.展开更多
In this work,a new design of ternary core-shell nanostructures of Au@ZnO-Pd was demonstrated to realize the synergetic utilization of a plasmonic effect and an electron-trapping co-catalyst for enhanced photocatalytic...In this work,a new design of ternary core-shell nanostructures of Au@ZnO-Pd was demonstrated to realize the synergetic utilization of a plasmonic effect and an electron-trapping co-catalyst for enhanced photocatalytic performance.In the ternary hybrid nanostructures,ZnO provides photo-generated carriers with higher redox ability,under UV-visible light,and Au nanocrystals perform the plasmonic hot electron injection as well as the local electromagnetic field enhancement of ZnO photoexcitation.Meanwhile,the Pd NPs can efficiently trap the generated electrons to govern the directional separation of the charge carriers.The efficient charge carrier separation in the ternary hybrid nanostructures was confirmed by steady-state PL spectra,time-resolved PL decay spectra,and transient photocurrent responses.The photocatalytic activity of the Au@ZnO-Pd nanostructures was evaluated by photodegrading phenol and methylene blue,respectively,under simulated sunlight(λ=360-780 nm),and the results showed that the Au@ZnO-Pd nanostructures gained a great enhancement of photocatalysis compared with ZnO,ZnO-Pd and Au@ZnO.Moreover,the effect of Pd loading content in the Au@ZnO-Pd nanostructures on the photocatalytic efficiency was studied within a certain range,indicating that the Au@ZnO-Pd photocatalyst with ~1.8 wt%Pd loading exhibited the best photocatalytic activities for photodegrading both phenol and methylene blue.The generation and effect of active species in the photocatalytic process were investigated using ESR testing and radical scavenging experiments.As a consequence,the integration of the ternary Au@ZnO-Pd core-shell nanostructures could achieve collective effects to greatly increase the photocatalytic efficiency.展开更多
Surface plasmons are collective excitations of conduction electrons situated at the metal-dielectric interface,resulting in markedly enhanced light–matter interactions.The high local field intensity has enabled a wid...Surface plasmons are collective excitations of conduction electrons situated at the metal-dielectric interface,resulting in markedly enhanced light–matter interactions.The high local field intensity has enabled a wide range of novel physical phenomena and innovative applications.However,the small mode volume and the femtosecond dynamics necessitate rigorous experimental conditions for complete characterizations.The demand for subwavelength resolution has outpaced the capabilities of conventional methods,prompting the development of novel characterization instruments.These instruments utilize two categories of probes with exceptional resolution:nanoscale tips and electron beams.The former has led to the emergence of scanning near-field optical microscopies,while the latter has resulted in electron nanoscopies.These technologies offer ultrahigh spatiotemporal resolutions in the multi-dimensional characterization of surface plasmons.Although advanced characterization technologies have promoted multi-dimensional manipulations of surface plasmons,quantum detection is still a challenge for them.This review article provides a comprehensive overview of the recent advances in plasmonics from the perspectives of near-field optics and electron nanoscopy.It introduces the latest characterization technologies and the manipulation of surface plasmons,including their spatial distribution,energy,momentum,and polarization.Additionally,the article describes advances and challenges in quantum plasmonics and the upgrade of characterization as a potential technical solution.Keywords:surface plasmons;plasmonics;electron nanoscopy;cathodoluminescence.展开更多
Tunable plasmonic structures provide the possibility to actively modify the radiation from atoms through electromagnetic coupling.In this paper,we investigate the decay and radiation behavior of an atom near a dielect...Tunable plasmonic structures provide the possibility to actively modify the radiation from atoms through electromagnetic coupling.In this paper,we investigate the decay and radiation behavior of an atom near a dielectric nanosphere with conductive surface within the framework of macroscopic quantum electrodynamics.The electromagnetic fields including the losses in the materials can be taken as fundamental excitations which interact with the atom through a transition dipole.Both weak and strong coupling regimes have been investigated.The decay rate and the angle-dependent light intensities indeed strongly depend on the parameters of the system,i.e.,the position and orientation of the dipole,the geometric size,and the surface conductivity,providing the opportunity of artificial control over these quantities.Generalizing the formalism in this paper to other systems,like metamaterials,is straightforward,which we believe may pave a way for future active quantum nanophotonic devices.展开更多
Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intri...Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intrinsic quantum efficiency (QE) and the stability oflight emitters. For this reason, it is broadly accepted that with the advent of highly efficient (QE close to 1) and stable emitters, thefundamental research phase of SSL is coming to an end. In this study, we demonstrate a very large improvement in SSL emission (above70-fold directional enhancement for p-polarized emission and 60-fold enhancement for unpolarized emission) using nanophotonicstructures. This is attained by coupling emitters with very high QE to collective plasmonic resonances in periodic arrays of aluminumnanoantennas. Our results open a new path for fundamental and applied research in SSL in which plasmonic nanostructures are able tomold the spectral and angular distribution of the emission with unprecedented precision.展开更多
Chirality, which describes the broken mirror symmetry in geometric structures, exists macroscopically in our daily life as well as microscopically down to molecular levels. Correspondingly, chiral molecules interact d...Chirality, which describes the broken mirror symmetry in geometric structures, exists macroscopically in our daily life as well as microscopically down to molecular levels. Correspondingly, chiral molecules interact differently with circularly polarized light exhibiting opposite handedness(left-handed and right-handed). However, the interaction between chiral molecules and chiral light is very weak. In contrast, artificial chiral plasmonic structures can generate "super-chiral" plasmonic near-field, leading to enhanced chiral light-matter(or chiroptical) interactions. The "super-chiral" near-field presents different amplitude and phase under opposite handedness incidence, which can be utilized to engineer linear and nonlinear chiroptical interactions. Specifically,in the interaction between quantum emitters and chiral plasmonic structures, the chiral hot spots can favour the emission with a specific handedness. This article reviews the state-of-the-art research on the design, fabrication and chiroptical response of different chiral plasmonic nanostructures or metasurfaces. This review also discusses enhanced chiral light-matter interactions that are essential for applications like chirality sensing, chiral selective light emitting and harvesting. In the final part, the review ends with a perspective on future directions of chiral plasmonics.展开更多
Graphene is emerging as a promising material for photonic applications owing to its unique optoelectronic properties.Graphene supports tunable,long-lived and extremely confined plasmons that have great potential for a...Graphene is emerging as a promising material for photonic applications owing to its unique optoelectronic properties.Graphene supports tunable,long-lived and extremely confined plasmons that have great potential for applications such as biosensing and optical communications.However,in order to excite plasmonic resonances in graphene,this material requires a high doping level,which is challenging to achieve without degrading carrier mobility and stability.Here,we demonstrate that the infrared plasmonic response of a graphene multilayer stack is analogous to that of a highly doped single layer of graphene,preserving mobility and supporting plasmonic resonances with higher oscillator strength than previously explored single-layer devices.Particularly,we find that the optically equivalent carrier density in multilayer graphene is larger than the sum of those in the individual layers.Furthermore,electrostatic biasing in multilayer graphene is enhanced with respect to single layer due to the redistribution of carriers over different layers,thus extending the spectral tuning range of the plasmonic structure.The superior effective doping and improved tunability of multilayer graphene stacks should enable a plethora of future infrared plasmonic devices with high optical performance and wide tunability.展开更多
Recently hybrid plasmonic waveguides have been becoming very attractive as a promising candidate to realize next-generation ultra-dense photonic integrated circuits because of the ability to achieve nano-scale confine...Recently hybrid plasmonic waveguides have been becoming very attractive as a promising candidate to realize next-generation ultra-dense photonic integrated circuits because of the ability to achieve nano-scale confinement of light and relatively long propagation distance. Furthermore, hybrid plasmonic waveguides also offer a platform to merge photonics and electronics so that one can realize ultra-small optoelectronic integrated circuits （OEICs） for high-speed signal generation, processing as well as detection. In this paper, we gave a review for the progresses on various hybrid plasmonic wave- guides as well as ultrasmall functionality devices developed recently.展开更多
Dynamic plasmonics with the real-time active control capability of plasmonic resonances attracts much interest in the communities of physics,chemistry,and material science.Among versatile reconfigurable strategies for...Dynamic plasmonics with the real-time active control capability of plasmonic resonances attracts much interest in the communities of physics,chemistry,and material science.Among versatile reconfigurable strategies for dynamic plasmonics,electrochemically driven strategies have garnered most of the attention.We summarize three primary strategies to enable electrochemically dynamic plasmonics,including structural transformation,carrier-density modulation,and electrochemically active surrounding-media manipulation.The reconfigurable microstructures,optical properties,and underlying physical mechanisms are discussed in detail.We also summarize the most promising applications of dynamic plasmonics,including smart windows,structural color displays,and chemical sensors.We suggest more research efforts toward the widespread applications of dynamic plasmonics.展开更多
Plasmonics based on localized surface plasmon resonance （LSPR） has found many exciting appli- cations recently. Those applications usually require a good morphological and structural control of metallic nanostructur...Plasmonics based on localized surface plasmon resonance （LSPR） has found many exciting appli- cations recently. Those applications usually require a good morphological and structural control of metallic nanostructures. Oblique angle deposition （OAD） has been demonstrated as a powerful technique for various plasmonic applications due to its advantages in controlling the size, shape, and composition of metallic nanostructures. In this review, we focus on the fabrication of metallic nanostructures by OAD and their applications in plasmonics. After a brief introduction to OAD technique, recent progress of applying OAD in fabricating noble metallic nanostructures for LSPR sensing, surface-enhanced Raman scattering, surface-enhanced infrared absorption, metal-enhanced fluorescence, and metamaterials, and their corresponding properties are reviewed. The future requirements for OAD plasmonics applications are also discussed.展开更多
Nanoscale plasmonic systems combine the advantages of optical frequencies with those of small spatial scales, circumventing the limitations of conventional photonic systems by exploiting the strong field confinement o...Nanoscale plasmonic systems combine the advantages of optical frequencies with those of small spatial scales, circumventing the limitations of conventional photonic systems by exploiting the strong field confinement of surface plasmons. As a result of this miniaturization to the nanoscale, electron microscopy techniques are the natural investigative methods of choice. Recent years have seen the development of a number of electron microscopy techniques that combine the use of electrons and photons to enable unprecedented views of surface plasmons in terms of combined spatial, energy, and time resolution. This review aims to provide a comparative survey of these different approaches from an experimental viewpoint by outlining their respective experimental domains of suitability and highlighting their complementary strengths and limitations as applied to plasmonics in particular.展开更多
To address the challenges of complex metallic film coating processes and low integration in single-parameter detection for existing photonic crystal fiber surface plasmon resonance(PCF-SPR)sensors,a dual-parameter sen...To address the challenges of complex metallic film coating processes and low integration in single-parameter detection for existing photonic crystal fiber surface plasmon resonance(PCF-SPR)sensors,a dual-parameter sensor based on gold nanowire-integrated bias-core PCF-SPR is proposed.Unlike conventional in-hole coatings or metallic film structures,the gold nanowires are directly attached to the fiber cladding via chemical vapor deposition(CVD),eliminating uneven coating issues and significantly simplifying fabrica-tion.By optimizing the asymmetric bias-core fiber structure and leveraging the strong localized field en-hancement of gold nanowires,the sensor achieves high-sensitivity synchronous detection of temperature(25−60℃)and refractive index(1.31−1.40)in dual-polarization modes.The simulation results demonstrate that the x-polarization mode can achieve 1.31−1.40 refractive index detection with maximum wavelength sensitivity and amplitude sensitivity of 14800 nm/RIU and−1724.25 RIU^(−1),and maximum refractive index resolution of 6.75×10^(−6)RIU.The y-polarization mode achieves refractive index detection range of 1.34−1.40,and the maximum wavelength sensitivity and amplitude sensitivity are 28400 nm/RIU and−1298.93 RIU^(−1),and the maximum refractive index resolution is 3.52×10^(−6)RIU.For temperature sensing,the sensor exhibits a wavelength sensitivity of 7.8 nm/℃and a high resolution of 1.38×10^(−6)℃over the range of 25−60℃.This design synergizes gold nanowires and the bias-core architecture to simplify fabrication while enabling multi-parameter detection.The proposed sensor offers new insights for integrated applications in biochemical mon-itoring,environmental sensing,and related fields.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 11804288)the Key Scientific Research Project of Higher Education Institutions in Henan Province, China (Grant No. 20231205164502999)。
文摘Negative friction refers to a frictional force that acts in the same direction as the motion of an object, which has been predicted in terahertz(THz) gain systems [Phys. Rev. B 108 045406(2023)]. In this work, we investigate the enhancement of the negative friction experienced by nanospheres placed near a graphene substrate. We find that the magnitude of negative friction is related to the resonant coupling between the surface plasmon polaritons(SPPs) of the graphene and localized surface phonon polaritons(LSPh P) of nanospheres. We exam nanospheres consisted of several different materials, including SiO_(2), Si C, Zn Se, Na Cl, ln Sb. Our results suggest that the LSPh P of Na Cl nanospheres match effectively with the amplified SPPs of graphene sheets. The negative friction for Na Cl nanospheres can be enhanced about one-to-two orders of magnitude compared to that of silica(SiO_(2)) nanospheres. At the resonant peak of negative friction, the required quasi-Fermi energy of graphene is lower for Na Cl nanospheres. Our finds hold great prospects for the mechanical manipulations of nanoscale particles.
基金Project supported by the ONR MURI(Grant No.N00014-10-1-0942)
文摘The rise of plasmonic metamaterials in recent years has unveiled the possibility of revolutionizing the entire field of optics and photonics, challenging well-established technological limitations and paving the way to innovations at an unprecedented level To capitalize the disruptive potential of this rising field of science and technology, it is important to be able to combine the richness of optical phenomena enabled by nanoplasmonics in order to realize metamaterial components, devices, and systems of increasing complexity. Here, we review a few recent research directions in the field of plasmonic metamaterials, which may foster further advancements in this research area. We will discuss the anomalous scattering features enabled by plasmonic nanoparticles and nanoclusters, and show how they may represent the fundamental building blocks of complex nanophotonic architectures. Building on these concepts, advanced components can be designed and operated, such as optical nanoantennas and nanoantenna arrays, which, in turn, may be at the basis of metasurface devices and complex systems. Following this path, from basic phenomena to advanced functionalities, the field of plasmonic metamaterials offers the promise of an important scientific and technological impact, with applications spanning from medical diagnostics to clean energy and information processing.
文摘This paper presents a review of recent investigational studies on exciting Surface Plasmon Polaritous (SPPs)in MicroWave (MW)and TeraHertZ (THz)regimes by using subwavelength corrugated patterns on conductive or metal surfaces.This article also describes SPP Microstrip (MS)structures at microwave and terahertz frequencies, and compares their significance with that of conventional MS Transmission Lines (TL),in order to tackle the key challenges of high gain,bandwidth size,compactness,TL losses,and signal integrity in high-end electronic de- vices.Because they have subwavelength properties,surface plasmon polaritous are gaining attention for their improved performance and ability for miniaturization in high-speed dense circuits.They possess comparably minuscule wavelength compared to incident light (photons).Consequently,they can demonstrate stronger spatial confinement and higher local field intensity at optical frequencies.In addition to engineering spoof SPP waveguides,which are created by engraving grooves and slits on metal surfaces to allow operation on at low frequencies (microwave and terahertz),semiconductors with smaller permittivity values and thus lower free charge carrier concentration have been demonstrated as a potential candidate in plasmonic devices.If necessary,further tuning of semiconductor-based SPP structures is aided by controlling the charge carrier concentration through doping,or by external stimuli such as optical illumination or thermal excitation of charge carriers from valence to conduction bands.This article conclusively covers previously elucidated perspectives on manipulating SSPPs in the MW and THz ranges,and emphasizes how these could steer next-generation plasmonic devices.
基金supported by the National Natural Science Foundation of China(Nos.61774062,11674107,61475049 and 11674109)the Natural Science Foundation of Guangdong Province in China(No.2016A030313443)
文摘In this paper, a plasmonics refractive index sensor with the semiring-stub system coupled to a bus waveguide is proposed. The structure can achieve wavelength band tunable and ultra-sharp Fano resonance. The coupling mechanism between the bright mode and dark mode is investigated in detail, and apparent plasmon induced transparency(PIT) is realized on the resonance wavelength. The full width at half maximum(FWHM) of the resonant wavelength is modulated by adjusting the coupled distance. The sensitivity and figure of merit(FOM) of the proposed sensor can reach up to 600 nm/RIU and 120 on the visible region, respectively, and this performance can be helpful for designing the photonic integrated circuit and optical communication, in addition, it can be applied for bio-sensing.
基金supported by the National Basic Research Program of China(Grant No.2011CB922004)the National Natural Science Foundation of China(Grant No.11174059)
文摘We discuss a new class of phenomena that we call ＂spin plasmonics＂. It is motivated by three different recent trends of physics research： （i） spintronics, （ii） plasmonics, and （iii） topological properties as is exemplified by the quantized Hall effect. This involves the physics of the ＂magnetic surface plasmon＂ （MSP） which provides for an analog of the edge states discussed in the quantized Hall effect. Their properties can be easily tuned by an external magnetic field. They are coupled to the electromagnetic field and can be injected into metallic structures and induce spin and charge currents and hold the promise of miniturization of nonreciprocal devices.
基金This work was supported by Universidad Técnica Particular de Loja(UTPL-Ecuador)under the project:“Análisis de las propiedades térmicas del grafeno y zeolite”,Grant No.:PROY_INV_QU_2022_362.T.T.,M.G.,and C.V.G.wish to thank the Ecuadorian National Department of Sciences and Technology(SENESCYT).This work was partially supported by LNF-INFN:Progetto HPSWFOOD Regione Lazio-CUP I35F20000400005.
文摘Germanene nanostrips(GeNSs)have garnered significant attention in modern semiconductor technology due to their exceptional physical characteristics,positioning them as promising candidates for a wide range of applications.GeNSs exhibit a two-dimensional(buckled)honeycomb-like lattice,which is similar to germanene but with controllable bandgaps.The modeling of GeNSs is essential for developing appropriate synthesis methods as it enables understanding and controlling the growth process of these systems.Indeed,one can adjust the strip width,which in turn can tune the bandgap and plasmonic response of the material to meet specific device requirements.In this study,the objective is to investigate the electronic behav-ior and THz plasmon features of GeNSs(≥100 nm wide).A semi-analytical model based on the charge-carrier velocity of free-standing germanene is utilized for this purpose.The charge-carrier velocity of freestanding germanene is determined through the GW approximation(V_(F)=0.702×10^(6)m·s^(−1)).Within the width range of 100 to 500 nm,GeNSs exhibit narrow bandgaps,typi-cally measuring only a few meV.Specifically,upon analysis,it was found that the bandgaps of the investigated GeNSs ranged between 29 and 6 meV.As well,these nanostrips exhibit√q-like plasmon dispersions,with their connected plasmonic fre-quency(≤30 THz)capable of being manipulated by varying parameters such as strip width,excitation plasmon angle,and sam-ple quality.These manipulations can lead to frequency variations,either increasing or decreasing,as well as shifts towards larger momentum values.The outcomes of our study serve as a foundational motivation for future experiments,and further con-firmation is needed to validate the reported results.
文摘Nano-optics is an emergent research field in physics that appeared in the 1980s,which deals with light–matter optical interactions at the nanometer scale.In early studies of nano-optics,the main concern focus is to obtain higher optical resolution over the diffraction limit.The researches of near-field imaging and spectroscopy based on scanning near-field optical microscopy(SNOM)are developed.The exploration of improving SNOM probe for near-field detection leads to the emergence of surface plasmons.In the sense of resolution and wider application,there has been a significant transition from seeking higher resolution microscopy to plasmonic near-field modulations in the nano-optics community during the nano-optic development.Nowadays,studies of nano-optics prefer the investigation of plasmonics in different material systems.In this article,the history of the development of near-field optics is briefly reviewed.The difficulties of conventional SNOM to achieve higher resolution are discussed.As an alternative solution,surface plasmons have shown the advantages of higher resolution,wider application,and flexible nano-optical modulation for new devices.The typical studies in different periods are introduced and characteristics of nano-optics in each stage are analyzed.In this way,the evolution progress from near-field optics to plasmonics of nano-optics research is presented.The future development of nano-optics is discussed then.
文摘The surface plasmon polaritons of the topological insulator Bi2Se3 can be excited by using etched grating or grave structures to compensate the wave vector mismatch of the incident photon and plasmon. Here, we demonstrate novel gold grating/Bi2Se3 thin film/sapphire hybrid structures, which allow the excitation of surface plasmon polaritons propagating through nondestructive Bi2Se3 thin film with the help of gold diffractive gratings. Utilizing periodic Au surface structures,the momentum can be matched and the normal-incidence infrared reflectance spectra exhibit pronounced dips. When the width of the gold grating W(with a periodicity 2 W) increases from 400 nm to 1500 nm, the resonant frequencies are tuned from about 7000 cm-1 to 2500 cm-1. In contrast to the expected ■ dispersion for both massive and massless fermions,where q ~π/W is the wave vector, we observe a sound-like linear dispersion even at room temperature. This surface plasmon polaritons with linear dispersion are attributed to the unique noninvasive fabrication method and high mobility of topological surface electrons. This novel structure provides a promising application of Dirac plasmonics.
基金Project supported by the 111 Project,China(Grant No.D17021)the Changjiang Scholars and Innovative Research Team in University,China(Grant No.PCSIRT,IRT 16R07)
文摘The plasmonics Talbot effect in metallic layer with infinite periodic grooves is presented in this study. Numerical approach based on the finite element method is employed to verify the derived Talbot carpet on the non-illumination side. The groove depth is less than the metallic layer thickness; however, for specific conditions, surface plasmons polaritons(SPPs)can penetrate through grooves, propagate under the metallic layer, and form Talbot revivals. The geometrical parameters are specified via groove width, gap size, period, and wavelength, and their proper values are determined by introducing two opening ratio parameters. To quantitatively compare different Talbot carpets, we introduce new parameters such as R-square that characterizes the periodicity of Talbot images. The higher the R-square of a carpet, the more coincident with non-paraxial approximation the Talbot distance becomes. We believe that our results can help to understand the nature of SPPs and also contribute to exploring this phenomenon in Talbot-image-based applications, including imaging, optical systems, and measurements.
基金supported by the National Natural Science Foundation of China(Grant No.21471004)the Science Foundation of Zhejiang Sci-Tech University(Grant No.17062002-Y).
文摘In this work,a new design of ternary core-shell nanostructures of Au@ZnO-Pd was demonstrated to realize the synergetic utilization of a plasmonic effect and an electron-trapping co-catalyst for enhanced photocatalytic performance.In the ternary hybrid nanostructures,ZnO provides photo-generated carriers with higher redox ability,under UV-visible light,and Au nanocrystals perform the plasmonic hot electron injection as well as the local electromagnetic field enhancement of ZnO photoexcitation.Meanwhile,the Pd NPs can efficiently trap the generated electrons to govern the directional separation of the charge carriers.The efficient charge carrier separation in the ternary hybrid nanostructures was confirmed by steady-state PL spectra,time-resolved PL decay spectra,and transient photocurrent responses.The photocatalytic activity of the Au@ZnO-Pd nanostructures was evaluated by photodegrading phenol and methylene blue,respectively,under simulated sunlight(λ=360-780 nm),and the results showed that the Au@ZnO-Pd nanostructures gained a great enhancement of photocatalysis compared with ZnO,ZnO-Pd and Au@ZnO.Moreover,the effect of Pd loading content in the Au@ZnO-Pd nanostructures on the photocatalytic efficiency was studied within a certain range,indicating that the Au@ZnO-Pd photocatalyst with ~1.8 wt%Pd loading exhibited the best photocatalytic activities for photodegrading both phenol and methylene blue.The generation and effect of active species in the photocatalytic process were investigated using ESR testing and radical scavenging experiments.As a consequence,the integration of the ternary Au@ZnO-Pd core-shell nanostructures could achieve collective effects to greatly increase the photocatalytic efficiency.
基金supported by the National Natural Science Foundation of China(Nos.12027807 and 62225501)the National Key R&D Program of China(No.2020YFA0211300)the High-Performance Computing Platform of Peking University.
文摘Surface plasmons are collective excitations of conduction electrons situated at the metal-dielectric interface,resulting in markedly enhanced light–matter interactions.The high local field intensity has enabled a wide range of novel physical phenomena and innovative applications.However,the small mode volume and the femtosecond dynamics necessitate rigorous experimental conditions for complete characterizations.The demand for subwavelength resolution has outpaced the capabilities of conventional methods,prompting the development of novel characterization instruments.These instruments utilize two categories of probes with exceptional resolution:nanoscale tips and electron beams.The former has led to the emergence of scanning near-field optical microscopies,while the latter has resulted in electron nanoscopies.These technologies offer ultrahigh spatiotemporal resolutions in the multi-dimensional characterization of surface plasmons.Although advanced characterization technologies have promoted multi-dimensional manipulations of surface plasmons,quantum detection is still a challenge for them.This review article provides a comprehensive overview of the recent advances in plasmonics from the perspectives of near-field optics and electron nanoscopy.It introduces the latest characterization technologies and the manipulation of surface plasmons,including their spatial distribution,energy,momentum,and polarization.Additionally,the article describes advances and challenges in quantum plasmonics and the upgrade of characterization as a potential technical solution.Keywords:surface plasmons;plasmonics;electron nanoscopy;cathodoluminescence.
基金supported by Hangzhou Dianzi University(Grant No.KYS075621018)supported by the Natural Science Foundation of Zhejiang Province(Grant No.LY24A050004)。
文摘Tunable plasmonic structures provide the possibility to actively modify the radiation from atoms through electromagnetic coupling.In this paper,we investigate the decay and radiation behavior of an atom near a dielectric nanosphere with conductive surface within the framework of macroscopic quantum electrodynamics.The electromagnetic fields including the losses in the materials can be taken as fundamental excitations which interact with the atom through a transition dipole.Both weak and strong coupling regimes have been investigated.The decay rate and the angle-dependent light intensities indeed strongly depend on the parameters of the system,i.e.,the position and orientation of the dipole,the geometric size,and the surface conductivity,providing the opportunity of artificial control over these quantities.Generalizing the formalism in this paper to other systems,like metamaterials,is straightforward,which we believe may pave a way for future active quantum nanophotonic devices.
基金This work is part of the research program of the Foundation for Fundamental Research on Matter(FOM),which is financially supported by the Netherlands Organization for Fundamental Research(NWO)It is also part of an industrial partnership program between Philips and FOM.It is supported by NanoNextNL of the Government of the Netherlands and 130 partners.
文摘Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intrinsic quantum efficiency (QE) and the stability oflight emitters. For this reason, it is broadly accepted that with the advent of highly efficient (QE close to 1) and stable emitters, thefundamental research phase of SSL is coming to an end. In this study, we demonstrate a very large improvement in SSL emission (above70-fold directional enhancement for p-polarized emission and 60-fold enhancement for unpolarized emission) using nanophotonicstructures. This is attained by coupling emitters with very high QE to collective plasmonic resonances in periodic arrays of aluminumnanoantennas. Our results open a new path for fundamental and applied research in SSL in which plasmonic nanostructures are able tomold the spectral and angular distribution of the emission with unprecedented precision.
基金the Singapore National Research Foundation-Agence Nationale de la Recherche(Grant No.NRF2017-NRF-ANR0052DCHIRAL).
文摘Chirality, which describes the broken mirror symmetry in geometric structures, exists macroscopically in our daily life as well as microscopically down to molecular levels. Correspondingly, chiral molecules interact differently with circularly polarized light exhibiting opposite handedness(left-handed and right-handed). However, the interaction between chiral molecules and chiral light is very weak. In contrast, artificial chiral plasmonic structures can generate "super-chiral" plasmonic near-field, leading to enhanced chiral light-matter(or chiroptical) interactions. The "super-chiral" near-field presents different amplitude and phase under opposite handedness incidence, which can be utilized to engineer linear and nonlinear chiroptical interactions. Specifically,in the interaction between quantum emitters and chiral plasmonic structures, the chiral hot spots can favour the emission with a specific handedness. This article reviews the state-of-the-art research on the design, fabrication and chiroptical response of different chiral plasmonic nanostructures or metasurfaces. This review also discusses enhanced chiral light-matter interactions that are essential for applications like chirality sensing, chiral selective light emitting and harvesting. In the final part, the review ends with a perspective on future directions of chiral plasmonics.
基金the European Union Seventh Framework Programme under grant agreements no.625673 GRYPHON,no.604391European Union H2020 Programme under grant agreement no.696656 Graphene Flagship+2 种基金financial support from the Swiss National Science Foundation through project no.133583,NATO’s Public Diplomacy Division in the framework of‘Science for Peace’,European Union’s Horizon 2020 research and innovation program under grant agreement no.644956,FundacióPrivada Cellex,AGAUR 2014 SGR 1400 and 1623the Spanish Ministry of Economy and Competitiveness(grants SEV-2015-0522 and MAT2014-59096-P)the‘Fondo Europeo de Desarrollo Regional’(FEDER)through grant TEC2013-46168-R。
文摘Graphene is emerging as a promising material for photonic applications owing to its unique optoelectronic properties.Graphene supports tunable,long-lived and extremely confined plasmons that have great potential for applications such as biosensing and optical communications.However,in order to excite plasmonic resonances in graphene,this material requires a high doping level,which is challenging to achieve without degrading carrier mobility and stability.Here,we demonstrate that the infrared plasmonic response of a graphene multilayer stack is analogous to that of a highly doped single layer of graphene,preserving mobility and supporting plasmonic resonances with higher oscillator strength than previously explored single-layer devices.Particularly,we find that the optically equivalent carrier density in multilayer graphene is larger than the sum of those in the individual layers.Furthermore,electrostatic biasing in multilayer graphene is enhanced with respect to single layer due to the redistribution of carriers over different layers,thus extending the spectral tuning range of the plasmonic structure.The superior effective doping and improved tunability of multilayer graphene stacks should enable a plethora of future infrared plasmonic devices with high optical performance and wide tunability.
基金Acknowledgements This project was partially supported by the National Natural Science Foundation of China （Grant No. 11374263）, the National High-Tech R＆D program of China （863 program） （No. 2011AA010301）, Zhejiang Provincial Grant （No. Z201121938）, the Doctoral Fund of Ministry of Education of China （No. 20120101110094）.
文摘Recently hybrid plasmonic waveguides have been becoming very attractive as a promising candidate to realize next-generation ultra-dense photonic integrated circuits because of the ability to achieve nano-scale confinement of light and relatively long propagation distance. Furthermore, hybrid plasmonic waveguides also offer a platform to merge photonics and electronics so that one can realize ultra-small optoelectronic integrated circuits （OEICs） for high-speed signal generation, processing as well as detection. In this paper, we gave a review for the progresses on various hybrid plasmonic wave- guides as well as ultrasmall functionality devices developed recently.
基金jointly supported by the National Natural Science Foundation of China(Nos.12022403,61735008,51925204,and 11874211)Key Science and Technology Innovation Program of Shandong Province(No.2019JZZY020704)the Fundamental Research Funds for the Central Universities(Nos.021314380140 and 021314380150)。
文摘Dynamic plasmonics with the real-time active control capability of plasmonic resonances attracts much interest in the communities of physics,chemistry,and material science.Among versatile reconfigurable strategies for dynamic plasmonics,electrochemically driven strategies have garnered most of the attention.We summarize three primary strategies to enable electrochemically dynamic plasmonics,including structural transformation,carrier-density modulation,and electrochemically active surrounding-media manipulation.The reconfigurable microstructures,optical properties,and underlying physical mechanisms are discussed in detail.We also summarize the most promising applications of dynamic plasmonics,including smart windows,structural color displays,and chemical sensors.We suggest more research efforts toward the widespread applications of dynamic plasmonics.
文摘Plasmonics based on localized surface plasmon resonance （LSPR） has found many exciting appli- cations recently. Those applications usually require a good morphological and structural control of metallic nanostructures. Oblique angle deposition （OAD） has been demonstrated as a powerful technique for various plasmonic applications due to its advantages in controlling the size, shape, and composition of metallic nanostructures. In this review, we focus on the fabrication of metallic nanostructures by OAD and their applications in plasmonics. After a brief introduction to OAD technique, recent progress of applying OAD in fabricating noble metallic nanostructures for LSPR sensing, surface-enhanced Raman scattering, surface-enhanced infrared absorption, metal-enhanced fluorescence, and metamaterials, and their corresponding properties are reviewed. The future requirements for OAD plasmonics applications are also discussed.
文摘Nanoscale plasmonic systems combine the advantages of optical frequencies with those of small spatial scales, circumventing the limitations of conventional photonic systems by exploiting the strong field confinement of surface plasmons. As a result of this miniaturization to the nanoscale, electron microscopy techniques are the natural investigative methods of choice. Recent years have seen the development of a number of electron microscopy techniques that combine the use of electrons and photons to enable unprecedented views of surface plasmons in terms of combined spatial, energy, and time resolution. This review aims to provide a comparative survey of these different approaches from an experimental viewpoint by outlining their respective experimental domains of suitability and highlighting their complementary strengths and limitations as applied to plasmonics in particular.
文摘To address the challenges of complex metallic film coating processes and low integration in single-parameter detection for existing photonic crystal fiber surface plasmon resonance(PCF-SPR)sensors,a dual-parameter sensor based on gold nanowire-integrated bias-core PCF-SPR is proposed.Unlike conventional in-hole coatings or metallic film structures,the gold nanowires are directly attached to the fiber cladding via chemical vapor deposition(CVD),eliminating uneven coating issues and significantly simplifying fabrica-tion.By optimizing the asymmetric bias-core fiber structure and leveraging the strong localized field en-hancement of gold nanowires,the sensor achieves high-sensitivity synchronous detection of temperature(25−60℃)and refractive index(1.31−1.40)in dual-polarization modes.The simulation results demonstrate that the x-polarization mode can achieve 1.31−1.40 refractive index detection with maximum wavelength sensitivity and amplitude sensitivity of 14800 nm/RIU and−1724.25 RIU^(−1),and maximum refractive index resolution of 6.75×10^(−6)RIU.The y-polarization mode achieves refractive index detection range of 1.34−1.40,and the maximum wavelength sensitivity and amplitude sensitivity are 28400 nm/RIU and−1298.93 RIU^(−1),and the maximum refractive index resolution is 3.52×10^(−6)RIU.For temperature sensing,the sensor exhibits a wavelength sensitivity of 7.8 nm/℃and a high resolution of 1.38×10^(−6)℃over the range of 25−60℃.This design synergizes gold nanowires and the bias-core architecture to simplify fabrication while enabling multi-parameter detection.The proposed sensor offers new insights for integrated applications in biochemical mon-itoring,environmental sensing,and related fields.
