- 标题
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- 实验方案
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A nanosensor with ultra-high FOM based on tunable malleable multiple Fano resonances in a waveguide coupled isosceles triangular resonator
摘要： A simple plasmonic structure, which is made up of a metal baffle in the middle of the metal–insulator–metal (MIM) waveguide coupled with an isosceles triangular cavity, is reported to achieve triple Fano resonances. These Fano resonances are numerically calculated by the finite element method (FEM). Besides, the multimode interference coupled mode theory (MICMT) and the standing wave theory are used for analyzing the Fano resonances phenomenon. On the one hand, these three Fano resonances can be independently tuned by adjusting the structural parameters, which makes the design of highly integrated photonic circuits more flexible. On the other hand, the proposed structure is well malleable and can be easily extended to a quintuple Fano system by introducing a ring resonator. Furthermore, the suggested structure can act as a high efficient refractive index (RI) sensor, yielding a great sensitivity of 1200 nm/RIU and a ultra-high maximal figure of merit (FOM) value of 3.0 × 106. Comparing with other similar sensors, our structure has relatively good sensitivity and it is superior to other structures in the maximal FOM, which obviously demonstrates its excellent nano-sensing performance.
关键词： Multiple Fano resonances,Multimode interference coupled mode theory (MICMT),Refractive index (RI) sensor,Ultra-high FOM,Surface plasmon polaritons (SPPs)
更新于2025-09-23 15:21:01
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Experimental observation of hybrid TE-TM polarized surface waves supported by a hyperbolic metasurface
摘要： Hyperbolic metasurfaces have gained significant attention due to their extraordinary electromagnetic properties to control propagating plane waves, but the excitation and propagation of surface plasmon-polaritons at hyperbolic metasurfaces, called hyperbolic plasmons, have been experimentally observed only recently. However, the advantages of the hyperbolic plasmons, such as hybrid TE-TM polarization discussed below, are not yet fully revealed and analyzed. In this paper, we focus on the numerical and experimental characterization of surface waves in the frequency range from 2 to 8 GHz supported by a hyperbolic metasurface composed of anisotropic metallic Jerusalem crosses printed on a thin dielectric substrate. We show different shapes of equal frequency contours, which correspond to a plethora of excitation and propagation regimes of surface waves. The principal novelty of this work consists in the experimental demonstration of surface waves with hybrid, i.e., mixed TE-TM, polarization. Surface waves with hybrid polarization are a promising tool in a number of applications and phenomena, including polarization converters, plasmonic sensors, plasmon steering over a surface, optical forces, and spin-orbit photonics, and they highlight the impact of on-chip and planar networks.
关键词： hybrid TE-TM polarization,hyperbolic metasurfaces,anisotropic metallic Jerusalem crosses,surface plasmon-polaritons,equal frequency contours
更新于2025-09-23 15:21:01
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Electrical Phase Control Based on Graphene Surface Plasmon Polaritons in Mid-infrared
摘要： Phase modulation of light is the core of many optoelectronic applications, such as electro-optic switch, sensors and modulators. Graphene Surface plasmon polaritons (SPPs) exhibit unique properties in phase modulation including dynamic tunability, a small driving voltage and small device size. In this paper, the novel phase modulation capability of graphene SPPs in mid-infrared are confirmed through theory and simulation. The results show that graphene SPPs can realize continuous tuning of the phase shift at multiple wavelengths in mid-infrared, covering the phase range from 0° to 360°. Based on these results, a sandwich waveguide structure of dielectric–graphene–dielectric with a device length of 800 nm is proposed, which shows up to 381° phase modulation range at an operating wavelength of 6.55 μm, given a 1 V driving voltage. In addition, the structure size is much shorter than the wavelength in mid-infrared and can realize sub-wavelength operation. This work paves the way to develop graphene-based tunable devices for mid-infrared wave-front control.
关键词： Mid-infrared,phase modulation,graphene surface plasmon polaritons
更新于2025-09-23 15:19:57
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Numerical Investigation on Multiple Resonant Modes of Double-Layer Plasmonic Grooves for Sensing Application
摘要： A high-performance multi-resonance plasmonic sensor with double-layer metallic grooves is theoretically constructed by introducing a polymethyl methacrylate groove with a numerical simulation method. Multiple resonance wavelengths can be generated at the oblique incidence, and the number and feature of resonant mode for sensing detection is different for various incident angles. Specifically, at the incident angle of 30°, the reflection spectrum exhibits two resonant dips, in which the dip at the wavelength of 1066 nm has an extremely narrow line width of ~4.5 nm and high figure of merit of ~111.11. As the incident angle increases, the electric dipole mode gradually weakens, but the surface plasmon resonance and cavity resonance mode are enhanced. Therefore, for an incident angle of 65°, three resonance dips for sensing can be generated in the reflection spectrum to realize three-channel sensing measurement. These double-layer plasmonic grooves have potential in the development of advanced biochemical surface plasmon polariton measurements.
关键词： double-layer plasmonic grooves,surface plasmon polaritons,multi-resonance sensing
更新于2025-09-23 15:19:57
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A Broadband Tunable Terahertz Metamaterial Absorber Based on Single-Layer Complementary Gammadion-Shaped Graphene
摘要： We present a simple design of a broadband tunable metamaterial absorber (MMA) in the terahertz (THz) region, which consists of a single layer complementary gammadion-shaped (CGS) graphene sheet and a polydimethylsiloxane (PDMS) dielectric substrate placed on a continuous metal film. The Fermi energy level (Ef) of the graphene can be modulated dynamically by the applied DC bias voltage, which enables us to electrically control the absorption performance of the proposed MMA flexibly. When Ef = 0.8 eV, the relative bandwidth of the proposed MMA, which represents the frequency region of absorption beyond 90%, can reaches its maximal value of 72.1%. Simulated electric field distributions reveal that the broadband absorption mainly originates from the excitation of surface plasmon polaritons (SPPs) on the CGS graphene sheet. Furthermore, the proposed MMA is polarization-insensitive and has wide angles for both transverse-electric (TE) and transverse-magnetic (TM) waves in the broadband frequency range. The broadband absorption capacity of the designed MMA can be effectively adjusted by varying the Fermi energy level of graphene. Lastly, the absorbance of the MMA can be adjusted from 42% to 99.1% by changing the Ef from 0 eV to 0.8 eV, which is in agreement with the theoretical calculation by using the interference theory. Due to its simple structure and flexible tunability, the proposed MMA has potential application prospects in tunable filtering, modulators, sensing, and other multispectral devices.
关键词： graphene,surface plasmon polaritons,broadband tunable absorption,terahertz metamaterial absorber
更新于2025-09-23 15:19:57
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Field localization of hexagonal and short-range ordered plasmonic nanoholes investigated by cathodoluminescence
摘要： Plasmonic nanoholes have attracted significant attention among nanoplasmonic devices, especially as biosensing platforms, where nanohole arrays can efficiently enhance and confine the electromagnetic field through surface plasmon polaritons, providing a sensitive detection. In nanohole arrays, the optical resonances are typically determined by the inter-hole distance or periodicity with respect to the surface plasmon wavelength. However, for short-range ordered (SRO) arrays, the inter-hole distance varies locally, so the plasmon resonance changes. In this study, we investigate the local resonance of SRO nanoholes using a cathodoluminescence technique and compare it with hexagonally ordered nanoholes. The cathodoluminescence photon maps and resonance peak analysis reveal that the electric fields are confined at the edges of holes and that their resonances are determined by inter-hole distances as well as by their distributions. This demonstrates the Anderson localization of the electromagnetic waves showing locally enhanced electromagnetic local density of states in SRO nanoholes.
关键词： Anderson localization,biosensing,cathodoluminescence,Plasmonic nanoholes,surface plasmon polaritons
更新于2025-09-23 15:19:57
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Compact and low-power all-optical surface plasmon switches with isolated pump and data waveguides and a rectangular cavity containing nano-silver strips
摘要： In this paper, a plasmonic all-optical switch based on a novel topology is presented. The structure is composed of a rectangular cavity coupled with two cross waveguides. Several silver strips with a tapered pattern are inserted in the rectangular cavity to create a sharp edge in the transmission spectrum of the data signal. The cavity and waveguides are filled with a non-linear insulator with high Kerr-type nonlinearity. The vertical and horizontal waveguides are used for passing the data and pump signals, respectively. When in addition to the data signal, the pump signal is also applied, the refractive index of the Kerr material changes, which triggers the switching mechanism. Allocating two different paths for the data and pump signals results in a desirable isolation between these signals. The proposed switch is numerically simulated using finite difference time domain (FDTD) method. In order to verify the FDTD simulation results, the basic switch structure is also analyzed using the transmission line method. Compact size (considering two different input ports), low pumping intensity, simplicity, symmetrical structure, suitable isolation and high contrast ratios are the marked characteristics of the proposed all-optical switch. As a result, such a structure has the potential to be used in complex integrated optical circuits.
关键词： Surface plasmon polaritons,Transmission line method,Metal-insulator-metal waveguide,All-optical switch,Kerr effect,Metal strips
更新于2025-09-23 15:19:57
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Low-threshold stimulated emission in perovskite quantum dots: single-exciton optical gain induced by surface plasmon polaritons at room temperature
摘要： Colloidal perovskite quantum dots are candidate materials for solution-processable lasers, although stimulated emission in a semiconductor usually occurs in the multiexciton regime. Due to the quantum-confinement effect of semiconductor quantum dots, the non-radiative recombination transition dominates the relaxation of multiexcitons. Hence, the implementation of low-threshold stimulated emission of perovskite quantum dots in the single-exciton regime is meaningful. Herein, we show that this problem can be partially solved by employing a locally enhanced electric field. By applying the metal surface plasmon resonance energy-transfer effect, we demonstrate a considerable reduction of the optical gain threshold due to the newly generated coupling level induced by the local surface plasmon, and obtain optical gain in the single-exciton regime at room temperature in colloidal perovskite quantum dots. At the same time, we achieve a more than fourfold reduction in the amplified spontaneous emission threshold. This may provide a new concept for the further design of low-threshold stimulated emission colloidal nanocrystal lasers and even for improving their energy conversion efficiency.
关键词： surface plasmon polaritons,stimulated emission,optical gain,room temperature,perovskite quantum dots
更新于2025-09-23 15:19:57
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Plasmonic Demultiplexer With Tunable Output Power Ratio Based on Metal-Dielectric-Metal Structure and E7 Liquid Crystal Arrays
摘要： A novel tunable plasmonic demultiplexer is proposed and numerically investigated by finite element method(FEM). It consists of two half-nanodisk cavities and two sets of E7 liquid crystal arrays which are side-coupled to three metal-dielectric-metal(MDM) waveguides. The demultiplexer can split the input lights into two parts corresponding to port1(1310nm) and port2(1550nm). The Q-factors of port1 and port2 are 54.6 and 36, and the crosstalk values are -20.7dB and -29.9dB, respectively. Obviously, both channels have high Q-factors and low crosstalk value. Moreover, the E7 liquid crystal arrays play a key role in the whole structure, which makes the output power adjustable proportionally by adjusting the applied voltage. This novel feature greatly enriches the function of our demultiplexer. Using the electronical tunable birefringence characteristic of liquid crystal and its arrays structure paves a new way to realize practical on-chip plasmonic system, which can be widely used not only in demultiplexers but also in nanosensors, optical splitters, filters, optical switches, nonlinear photonic and slow-light devices.
关键词： on-chip plasmonic system,demultiplexer,surface plasmon polaritons(SPPs),Metal-dielectric-metal(MDM) waveguide
更新于2025-09-23 15:19:57
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Spoof Surface Plasmon Polaritons Based Reconfigurable Band-Pass Filter
摘要： This letter reports the design and analysis of the bandwidth (B.W.) reconfigurable band-pass filter using spoof surface plasmon polaritons at THz/Microwave frequency. The designed filter consists of a spoof SPP T-shape resonator in which tuning has been introduced using variable capacitor device (having a cutoff frequency in THz regimes). Even and odd mode analysis has been carried out for a better understanding of the phenomenon. The proposed concept of variable bandwidth at a THz frequency in SSPP structure has been demonstrated through Co-EM simulation. For the experimental validation of the proposed approach, the filter has been designed at microwave frequency and developed on a 60 mil (1.52mm) thick microwave laminate and characterized using Keysight Field-Fox analyzer N9918A. In THz and microwave frequency regime, the designed filter has 3dB B.W. reconfigurability of 20GHz (0.41THz-0.43THz) and 300MHz (100MHz – 400MHz) with the insertion loss (I.L.) of ~3dB and ~1.7dB - 3.2dB respectively. The Proposed reconfigurable band-pass filter will pave an important role in the design and development of plasmonic circuits and systems.
关键词： bandwidth,reconfigurable,spoof surface plasmon polaritons,Band-pass filter
更新于2025-09-19 17:15:36