Fiber-based Surface Plasmon Resonance Sensor for Lead Ion Detection in Aqueous Solution
AbstractMaghemite/reduced graphene oxide nanocomposite has been successfully deposited onto the surface of a gold-coated D-shaped optical fiber. The synergetic combination of gold, graphene, and iron oxide nanoparticles has shown enhancement of the resonance field and sensitivity of the fiber-based plasmonic sensor. In particular, the sensor exhibited its capability to detect lead ions (Pb2+) in aqueous solution via monitoring the spectral response of the sensor probe to different concentrations of Pb2+. A sensor sensitivity of 1.2 nm per μg/L was attained at the lowest detected Pb2+ concentration, which is 0.001 ppm (l...
Source: Plasmonics - April 7, 2020 Category: Biomedical Science Source Type: research

Self-Referencing Plasmonic Array Sensors
AbstractA self-referencing plasmonic platform is proposed and analyzed. By introducing a thin gold layer below a periodic two-dimensional nano-grating, the structure supports multiple modes including localized surface plasmon resonance (LSPR), surface plasmon resonance (SPR), and Fabry-Perot resonances. These modes get coupled to each other creating multiple Fano resonances. A coupled mode between the LSPR and SPR responses is spatially separated from the sensor surface and is not sensitive to refractive index changes in the surrounding materials or surface attachments. This mode can be used for self-referencing the measur...
Source: Plasmonics - April 6, 2020 Category: Biomedical Science Source Type: research

1-D Metal-Dielectric-Metal Grating Structure as an Ultra-Narrowband Perfect Plasmonic Absorber in the Visible and Its Application in Glucose Detection
AbstractThe need for an easy to fabricate perfect and narrowband light absorber in the visible range of electromagnetic (EM) spectrum has always been in demand for many scientific and device applications. Here, we propose a metal-dielectric-metal (MDM) 1-D grating plasmonic structure as a perfect narrow band light absorber in the visible and its application in glucose detection. The proposed structure consists of a 1- D grating of gold on the top of a dielectric layer on a gold film. Optimization for dielectric grating index (n), grating thickness (t), grating width (W), and grating period (P) has been done to improve the ...
Source: Plasmonics - April 4, 2020 Category: Biomedical Science Source Type: research

Radiative and Non-radiative Surface Plasmon Resonance: Comparison of Real-Time Sensing Performance
AbstractThe work presents a surface plasmon resonance sensor able to operate the non-radiative and radiative surface plasmons simultaneously. The optical coupling between photons and surface plasmons was mediated by a rough surface, allowing the photon emission by radiative plasmons excitation process. Experimental tests with reversible and irreversible binding were performed, and the results were compared. The SPR curve profile indicates normalized values  1 for SP emission. This feature suggests the involvement of localized SP-states that co-exist in the film with delocalized propagating SP state. The data extract...
Source: Plasmonics - April 4, 2020 Category: Biomedical Science Source Type: research

A Broadband Single Polarization Photonic Crystal Fiber Filter Around 1.55  μm Based on Gold-Coated and Pentagonal Structure
AbstractIn this paper, a broadband single polarization photonic crystal fiber (PCF) filter around 1.55  μm is presented on account of surface plasmon resonance. The finite element method is used to investigate the performance of the filter, and the structure parameters’ influences on the performances of the filter are studied. Due to asymmetry which is caused by the pentagonal arranged cladding a ir holes, the confinement loss of the Y polarization core mode reaches to as high as 1751.05 dB/cm around 1.55 μm, while the loss for the X polarization mode is only 0.22 dB/cm. This indicates that ...
Source: Plasmonics - April 2, 2020 Category: Biomedical Science Source Type: research

Beam Steering of a Terahertz Semi Bow Tie Antenna Using Parasitic Graphene Ribbons
AbstractIn this paper, a reconfigurable beam-scanning planar antenna is proposed in terahertz frequencies. The presented structure consists of a semi bow tie antenna surrounded by circularly arranged parasitic pieces of graphene. The performance of the proposed antenna is investigated considering three different states where a PEC ground plane and a graphene ground layer with chemical potentials 0 (mode A) and 1 (mode B) are utilized at the bottom of the substrate. The proposed antenna is designed for utilization at a specific frequency of 1.2  THz in all these three states. The achieved antenna boresight and radiatio...
Source: Plasmonics - April 1, 2020 Category: Biomedical Science Source Type: research

D-Shaped Photonic Crystal Fiber –Based Surface Plasmon Resonance Biosensors with Spatially Distributed Bimetallic Layers
AbstractThis paper deals with the development and analysis of D-Shaped photonic crystal fiber (PCF) biosensors using surface plasmon resonance (SPR). A thin metal layer is deposited on the outer flat surface of the PCF that behaves as the plasmonic material. Analyte is filled in the outermost peripheral region of metal layer. Finite element method (FEM) with perfectly matched layer (PML) is applied to analyze the proposed sensors. Mode analysis is performed on the proposed structures to evaluate various parameters of SPR-based PCF sensors. Three D-shaped PCF structures have been proposed with silver (Ag), gold (Au) and two...
Source: Plasmonics - April 1, 2020 Category: Biomedical Science Source Type: research

Plasmonic Broadband Perfect Absorber for Visible Light Solar Cells Application
AbstractSolar radiation is mainly concentrated in visible light region (50%), to achieve the perfect absorption of this spectral band is significant for many energy-related fields include solar cells, hot-electron devices, and perfect cloaking. In this paper, we theoretically designed and numerically demonstrated a broadband perfect absorber that works in visible light (400 –800 nm). The perfect absorber consists of silica-titanium nitride-silica-titanium nitride four-layer structure, which has an ultra-thin thickness of 325 nm. This broadband absorber can continuously achieve light absorption from 400 to 800 nm, wit...
Source: Plasmonics - March 13, 2020 Category: Biomedical Science Source Type: research

An Angle-Insensitive Metamaterial Absorber Based on the Gravity Field Regulation
AbstractIn this paper, we propose a novel gravity-tailored absorber to achieve two different absorption peaks at two different frequencies, whose improvement is based on the traditional sandwich structure. It is unusual that two dug grooves inside are filled with the liquid dielectrics. Since existing the gravity field, rotating this absorber in thexy plane will make the absorption peak change. In addition, this gravity-tailored absorber has a good stability of the incidence angle. The discussion of the power flow, the electric field, and structure parameters are also given to explain the physical mechanism. Compared with ...
Source: Plasmonics - March 13, 2020 Category: Biomedical Science Source Type: research

Refractive Index Sensor Based on Surface Plasmon Resonance Excitation in a D-Shaped Photonic Crystal Fiber Coated by Titanium Nitride
AbstractIn this paper, a plasmonic refractive index sensor using a D-shaped photonic crystal fiber coated by titanium nitride has been proposed. The interaction and interplay between fiber fundamental mode and plasmonic mode which lead to the formation of resonance peaks depending on the analyte refractive index (RI) are explained in detail. Using both spectral and amplitude sensitivity methods, the sensing performance of the proposed sensor for detecting high-index analytes is numerically investigated. The proposed PCF-SPR sensor has a RI detection range of 1.44 to 1.52 and exhibits two linear sensing regions with an aver...
Source: Plasmonics - March 13, 2020 Category: Biomedical Science Source Type: research

Study of Energy Harvesting from Low-Frequency Vibration with Ferromagnetic Powder and Non-magnetic Fluid
In this study, an electrical generator was created by the electromagnetic induction method by putting a small mass of ferromagnetic powder in nonmagnetic fluid. A broadband vibration energy harvesting model was created in which vibrations are broadened through a multi-degree of freedom oscillation system using ferromagnetic powder. To generate electricity from low-frequency vibrations (1 Hz or less), a non- resonant type model was created by adding fluid to the ferromagnetic powder model and the simulation results confirmed using computational fluid dynamics by creating a working energy harvesting device. (Source: Plasmonics)
Source: Plasmonics - March 13, 2020 Category: Biomedical Science Source Type: research

Leaky Wave Antenna Based on Periodically Truncated SSPP Waveguide
AbstractThe guided waveguide structures based on surface plasmons can be used to miniaturize microwave devices. By simply introducing a series of periodic truncation slits in the SSPP (spoof surface plasmon polariton) waveguide, three frequency regions, namely radiating spatial wave region, guiding SSPP mode region, and the cut-off region, are formed. In the frequency region of radiation, the SSPP mode can be transitioned to spatial wave. Consequently, double-port leaky wave antenna based on SSPP waveguide is realized with beam sweep function. Furthermore, a single-port antenna is demonstrated by symmetrical halving of the...
Source: Plasmonics - March 13, 2020 Category: Biomedical Science Source Type: research

Analysis and Simulation of a Novel Localized Surface Plasmonic Highly Sensitive Refractive Index Sensor
AbstractDividing a metal nanoparticle into smaller components and the occurrence of the plasmonic phenomenon in the gap between these components can improve the sensitivity of the detector to variation of the refraction coefficient of liquid. In this paper, in a constant volume of metal, a golden disk is divided into two rings and one smaller disk. With a proper arrangement of these components, the surface plasmon resonance phenomenon takes place at the wavelength of 945.7  nm. The occurrence of this phenomenon increases the field in the distance between nanoparticles surrounded by liquid. The sensitivity of the detec...
Source: Plasmonics - March 12, 2020 Category: Biomedical Science Source Type: research

Bound States in the Continuum in a T-Shape Nanohole Array Perforated in a Photonic Crystal Slab
AbstractWe have studied the reflectance spectra of T-shape nanohole array in a layer of Photonic crystal (PhC) slab. Results show that light can be confined perfectly in the PhC slab at a given incident angle at a suitable hole shape, hole size, layer thickness, and refractive index of surrounding medium. We obtained that the Q-factor at BIC can exceed 105, and the wavelength, incident angle of BIC can be modulated by structure parameters and surrounding mediums dielectric factor. Especially, the BIC has high sensitivity to the refractive index of the surrounding medium. The results can be helpful in the design of new-type...
Source: Plasmonics - March 7, 2020 Category: Biomedical Science Source Type: research

Optical Properties of Au-Ag Bimetallic Nanoparticles of Different Shapes for Making Efficient Bimetallic-Photonic Whispering Gallery Mode Hybrid Microresonators
AbstractFor the first time, we propose a bimetallic-photonic whispering gallery mode (WGM) hybrid microresonator for the detection and sizing of single protein molecules in real time. To optimize the sensitivity of hybrid microresonators, theoretical simulations have been carried out to understand the optical properties of different types of Au-Ag bimetallic nanoparticles such as solid nanospheres, dielectric core-bimetallic nanoshells, nanostars, and nanoprisms using Lorenz-Mie theory, Aden-Kerker theory, and finite element method (FEM). The role of size and Au-Ag ratio on the optical properties of the nanospheres and nan...
Source: Plasmonics - March 6, 2020 Category: Biomedical Science Source Type: research

Theory of Optical Coupling Effects Among Surfactant Au Nanoparticles Films
AbstractIn previous reports, Dalfovo et al. showed experimentally that thin films of Au nanoparticles (NP) with organic coating change their optical properties when exposed to several analytes in the vapor phase (Anal Chem 84:4886 –48922012; J Phys Chem C 119:5098 –51062015). This optical behavior was associated with changes in the mean distance between nanoparticles, which resulted in a displacement of their plasmon bands towards blue or red in the presence of toluene (Tol) or ethanol (EtOH) vapors, respectively. In the report by Dalfovo et al. (J Phys Chem C 119:5098 –51062015), in-situ grazing-incidenc...
Source: Plasmonics - March 3, 2020 Category: Biomedical Science Source Type: research

BaTiO 3 -Graphene-Affinity Layer –Based Surface Plasmon Resonance (SPR) Biosensor for Pseudomonas Bacterial Detection
AbstractIn the present work, a highly sensitive SPR biosensor based on silver (Ag), barium titanate (BaTiO3), graphene, and affinity layer is proposed for the detection ofPseudomonas bacteria. The performance of this proposed sensor has been numerically studied and analyzed for sensitivity, quality parameter, and detection accuracy. The proposed structure used attenuated total reflection (ATR) approach based on the Kretschmann configuration for the investigation of performance parameters. The inclusion of the BaTiO3 layer along with the affinity layer shows the enhancement in the performance of the proposed structure for t...
Source: Plasmonics - March 2, 2020 Category: Biomedical Science Source Type: research

Zirconium Nitride for Plasmonic Cloaking of Visible Nanowire Photodetectors
AbstractLight scattered by a photodetector disturbs the probing field, resulting in noise. Cloaking is an effective method to reduce this noise. Here we investigate theoretically an emerging plasmonic material, zirconium nitride (ZrN), as a plasmonic cloak for silicon (Si) nanowire-based photodetectors and compare it with a traditional plasmonic material, gold (Au). Using Mie formalism, we have obtained the scattering cancelation across the visible spectrum. We found that ZrN cloaks produce a significant decrease in the scattering from bare Si nanowires, which is 40% greater than that obtained with Au cloaks in the wavelen...
Source: Plasmonics - March 2, 2020 Category: Biomedical Science Source Type: research

Intriguing Plasmonic and Fluorescence Duality in Copper Nanoparticles
AbstractDendrimeric copper nanoparticles (CuNPs) were prepared by the reduction of [Cu2(CH3CO2)4] with ascorbic acid at 75  °C in the presence of ranelate ions. The metallic nanoparticles exhibited a strong plasmonic band centered at 581 nm, and their average size distribution was typically in the range of 20–30 nm. By adding polyvinylpyrrolidone to the reaction mixture, the growth of the initial copper nanopartic les was hindered. Their sizes were stabilized around 1.8 nm, leading to spherical agglomerates of about 50 nm. Upon green light excitation, the agglomerates exhibited yellow-ora...
Source: Plasmonics - February 28, 2020 Category: Biomedical Science Source Type: research

Interfacial Growth of Activated Carbon on WO 3 Nanoplates for Enhanced Photocatalytic Activity by Surface Plasmon Resonance
This study considers the photo-degradation of paracetamol by photocatalysis process, under visible-light irradiation. To study the properties of the prepared materials, SEM, TEM, FTIR, PL, and UV were performed. SEM was used to find the structure and size of the prepared materials. FTIR was used to analyze the presence of functional groups in the material. PL and UV were used to analyze the optical properties of the prepared materials. The SEM images of the prepared sample of WO3 showed that it has structure-like nanocubic and rectangular rods which become sharper by addition of carbon nanoparticles. The average size of th...
Source: Plasmonics - February 18, 2020 Category: Biomedical Science Source Type: research

Graphene-Based Composite Right/Left-Handed Leaky-Wave Antenna at Terahertz
AbstractIn this paper, a simple terahertz (THz) leaky-wave antenna (LWA) composed of periodic gapped graphene ribbons and a silicon substrate is presented. The graphene sheets of the antenna operate in an electric field with a resonance distribution of transverse electric (TE) surface plasmon polaritons (SPPs). The THz LWA has both negative and positive propagation constant with the variation of frequencies. Thus, the LWA performs as a composite right/left-handed (CRLH) LWA with backfire-to-endfire beam steering capability in the THz band. The working principle of the THz LWA is analyzed in detail using the theory of dispe...
Source: Plasmonics - February 18, 2020 Category: Biomedical Science Source Type: research

An Analytical Study of Magneto-Plasmons in Anisotropic Multi-layer Structures Containing Magnetically Biased Graphene Sheets
This article proposes a novel analytical model for the anisotropic multi-layer structures containing magnetically biased graphene sheets. The multi-layer structure is composed of various magnetic materials, each one has the permittivity and permeability tensors of\( \overline{\overline{\upvarepsilon}} \) and\( \overline{\overline{\mu}} \), respectively. An external magnetic field is applied, normal to the structure surface. Each graphene sheet, with anisotropic conductivity tensor (\( \overline{\overline{\sigma}} \)), has been sandwiched between two adjacent magnetic materials. Our model is used to find the dispersion rela...
Source: Plasmonics - February 16, 2020 Category: Biomedical Science Source Type: research

Efficiency Enhancement of Ultra-thin CIGS Solar Cells Using Bandgap Grading and Embedding Au Plasmonic Nanoparticles
The objective of this study is to enhance the efficiency of copper indium gallium selenide (CIGS) solar cells. To accomplish that, composition grading of absorber layer was carried out by using SILVACO ’s technology aided computer design (TCAD) ATLAS program. Results showed a meaningful improvement of output parameters including open-circuit voltage (Voc), short-circuit current (Isc), fill factor (FF), and power conversion efficiency (η). For further performance improvement of the cell, Au plasmonic scattering nanoparticles were loaded on the top of the ZnO window layer. Plasmonic nanoparticles can restrict, abso...
Source: Plasmonics - February 13, 2020 Category: Biomedical Science Source Type: research

Fabrication of Sub-10-nm Plasmonic Gaps for Ultra-Sensitive Raman Spectroscopy
AbstractThe past two decades have witnessed the explosion of activities in the field of surface enhanced Raman spectroscopy (SERS). SERS platforms employ nano-structures that excite plasmonic modes with large local electromagnetic fields localized within small gap spaces between each constituting feature. Although the research-oriented SERS platforms yield significant signal enhancements to identify even single molecules, practical SERS-based sensors have not been fully introduced yet. The main reason behind this absence is the need for a cost-effective and reliable manufacturing method for controllable fabrication of plas...
Source: Plasmonics - February 10, 2020 Category: Biomedical Science Source Type: research

Absorption Circular Dichroism Induced by Contorted Electrical Oscillations in Rectangular Nanoholes
AbstractThe chiroptical response of plasmonic chiral nanostructures can be tuned by combining different structures. In this paper, an L-shaped metal strip is introduced into a rectangular metal nanohole to generate absorption circular dichroism (ACD). The results of a finite-element method calculation show that ACD effects result from contorted electrical oscillations in the L-shaped strip. Additional calculations show that the ACD effects of the proposed metasurface depend strongly on the structure parameters. These findings provide not only a mechanism for enhancing chiroptical responses in planar structures but also a g...
Source: Plasmonics - February 8, 2020 Category: Biomedical Science Source Type: research

Carrier Dynamics in Ultrathin Gold Nanowires: Role of Auger Processes
AbstractCarrier dynamics in metallic nanostructures is strongly influenced by their confining dimensions. Gold nanoparticles of size\(\sim ~2\) nm which fill the transition space separating metallic and non-metallic behavior. In this work, we report carrier dynamics in high aspect ratio ultrathin gold nanowires (Au-UNWs) of average diameter\(\sim \) 2 nm using pump (3.1 eV) and coherent white light continuum as probe in the spectral range of 1.15 to 2.75 eV. The transient carrier dynamics in Au-UNWs under extreme excitation regime is slower than predicted by the often used two-temperature model. We identify Auger-assisted ...
Source: Plasmonics - February 7, 2020 Category: Biomedical Science Source Type: research

A Multifunctional Integrated Design of Simultaneous Unity Absorption and Polarization Conversion
AbstractHerein, an integrated multifunctional design for simultaneous perfect absorption and polarization conversion is proposed that worked in theKu band: the proposed structure consisted of two asymmetric dielectric semi-rings which are supported on a ground plane by two dielectric cylinders with different heights. Simulated results demonstrate that unity absorption and linear cross-polarization conversion can be integrated into one multifunctional structure: absorption and polarization conversion operate at different frequencies. Furthermore, these different functions under the different polarized modes (TE and TM) are ...
Source: Plasmonics - February 6, 2020 Category: Biomedical Science Source Type: research

Influence of Design Parameters on Multilayered Nanoplasmonic Structures in Modified Kretschmann-Raether Configurations
AbstractSurface Plasmon Resonance (SPR) technique has been of recent interest in many fields such as biological and chemical sensing, defense-related applications, etc. The introduction of graphene sheet (metal-like optical properties) over a thin-film layers plays a significant role in generating SPR. Different nanoplasmonic structures like Coupled Waveguide SPR (CWSPR) and Long  Range SPR (LRSPR) are considered with modified Kretschmann-Raether configurations for different wavelengths in visible range for plasmonic sensors application. Characteristic Transfer Matrix (CTM) method in MATLAB environment is employed to ...
Source: Plasmonics - February 4, 2020 Category: Biomedical Science Source Type: research

Waveguide-Coupled Surface Plasmon Resonance Sensor for Both Liquid and Gas Detections
AbstractIn this paper, we propose a novel surface plasmon resonance sensor for both liquid and gas detections, which is based on the two dielectric planar waveguide (PWG)-coupled plasmonic structure. Two sharp Fano-type resonances, which arise from the electromagnetic coupling between surface plasmon polariton (SPP) and PWG modes, appear in the reflection curve, and they can be used to monitor the minute changes of the refractive indices of gas and liquid due to their high imaging sensitivities (>  9.0 × 103 RIU− 1). The Fano resonance angles and the figures of merit for imaging sensitivity can...
Source: Plasmonics - February 3, 2020 Category: Biomedical Science Source Type: research

Lifetime of Enhanced Graphene Surface Plasmon and Superstrate Sensitivity
AbstractWe investigated the field enhancement and lifetime of tuning surface plasmon in zero-thickness nanostructured graphene patches. The graphene surface plasmon (GSP) resonance mechanism mainly originates from the contribution, that the periodical structure can provide strong coupling of GSP modes into the incident light field, which can enhance GSP resonance and the local field. And consequently, it facilitates the tuning of the patch modes by changing Fermi energy, carrier mobility, and superstrate refractive index, respectively. We can control precisely the resonant wavelengths, field enhancement, and lifetime of th...
Source: Plasmonics - January 30, 2020 Category: Biomedical Science Source Type: research

Plasmon-Assisted Crystalline Silicon Solar Cell with TiO 2 as Anti-Reflective Coating
AbstractThe present study focuses on the employment of TiO2 (titanium dioxide) film as an anti-reflective coating (ARC) on thin crystalline silicon (Si)-based solar cells along with the incorporation of plasmonic silver nanoparticles (Ag NPs) on its front surface having ITO (Indium Tin Oxide) as top metal contact. The response of solar cell has been studied in context of the external quantum efficiency (EQE) and the photovoltaic current-voltage characteristics. The EQE is enhanced appreciably in the entire wavelength range of 300 to 1100  nm (from 13.26% for bare Si solar cell to 61.93% for solar cell having both TiO2...
Source: Plasmonics - January 28, 2020 Category: Biomedical Science Source Type: research

Predicting the Size of Silver Nanoparticles from Their Optical Properties
In this study, localized surface plasmon resonance (LSPR) of the spherical silver nanoparticles (AgNPs) was evaluated based on experimental and theoretical viewpoints. In the experimental phase, a facile seed-mediated method was employed to synthesize spherical AgNPs with different sizes. As expected, an increase in the size of AgNPs resulted in a red-shift in LSPR peak position from 390 to 460  nm. Besides, the theoretical LSPR peak position of AgNPs was derived from Mie theory using different refractive indices databases. A comparison between the experimentally obtained data and the theoretical predictions indicated...
Source: Plasmonics - January 28, 2020 Category: Biomedical Science Source Type: research

Research on Transmission Characteristics of Two-Dimensional Superconducting Photonic Crystal in THz-Waves
AbstractIn this paper, the transmission characteristics of two-dimensional photonic crystal with Hg-1223 cylindrical array in transverse magnetic mode are studied in terahertz-waves by shift operator finite-difference time-domain method. The effects of external temperature and pressure and the period and radius of the dielectric cylinders on the transmission properties of superconducting photonic crystal in terahertz-waves are studied. The simulation results show that external temperature and pressure can be used to change the plasma frequency of superconductor, thus adjusting band gap width of superconducting photonic cry...
Source: Plasmonics - January 28, 2020 Category: Biomedical Science Source Type: research

Analysis of Dual-Channel Simultaneous Detection of Photonic Crystal Fiber Sensors
AbstractPhotonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) has broad application prospects in the detection of biological proteins, DNA/RNA, and toxic chemicals. However, there are many problems in application process, such as inhomogeneous metal nanofilm, low filling speed of analyte, and low detection efficiency, which limit the development of this technology. In this paper, a dual-channel PCF sensor based on simultaneous detection which has the advantages of SPR and PCF was proposed to improve the detection efficiency of samples. By optimizing the dielectric layer, the identification ability of...
Source: Plasmonics - January 27, 2020 Category: Biomedical Science Source Type: research

Numerical Analysis of Single Negative Broadband Metamaterial Absorber Based on Tri Thin Layer Material in Visible Spectrum for Solar Cell Energy Harvesting
AbstractA broadband nanostructure metamaterial absorber (MA) based on tri-layer metallic-optical-thin film molded shape is proposed for visible spectrum solar energy scavenging. This MA is investigated for photon mobility to achieve significant photon conversion and absorption to integrate into solar cell technology, IoT components, or energy harvesting. Design and analysis of the proposed MA were performed using the “Yee’s Finite-Difference Time-Domain (FDTD)” method based on commercially available CST microwave studio simulation software. Numerical computational tools depict an absorptivity of higher th...
Source: Plasmonics - January 25, 2020 Category: Biomedical Science Source Type: research

Surface-Enhanced Raman Scattering (SERS) on 1D Nano-gratings
AbstractSurface-enhanced Raman scattering (SERS) enhancement factor (EF) is among the major applications of surface plasmon polaritons (SPP ’s). In this work, the SERS EF of 1D rectangular and sinusoidal-shaped gold (Au) grating structures has been designed and optimized on Au film using COMSOL multiphysics (5.3a) RF module taking glass as substrate. The 1D grating models are simulated by variation in slit width ranging 200–600 nm while other parameters including periodicity of 700 nm and Au film thickness of 50 nm remained fixed. In order to study the several phenomena including enhanced optical...
Source: Plasmonics - January 25, 2020 Category: Biomedical Science Source Type: research

RCS Reduction from Conformal Surfaces Using Plasma-Based AMC Arrays
AbstractMilitary applications employ metallic objects with different shapes, which must produce low radar cross-section (RCS) to avoid detection and destruction from explosive devices. A plasma-based artificial magnetic conductor (AMC) unit cell with crossed arrow shape is employed for reconfigurable RCS reduction bandwidth from metallic objects. Loading metallic objects with AMC unit-cell elements changes its surface to high impedance surface which reduces the electromagnetic waves reflected from these objects.  The plasma material reconfigurable electric properties effect on controlling the RCS reduction bandwi...
Source: Plasmonics - January 24, 2020 Category: Biomedical Science Source Type: research

Tunable Plasmonic Resonances in Hexagonally Ordered Gold Nanostructure Arrays with Increasing Interstice Size
AbstractGold nanostructure arrays were fabricated by combining colloidal lithography with inclined reactive ion etching and inclinded sputtering. Field emission scanning electron microscopy studies of this substrate show uniaxial hexagonally ordered graded nanostructure arrays with increasing interstice at different positions. Optical spectroscopy studies in visible range reveal that these structures support localized surface plasmon resonance, surface plasmon polaritons, and hybridized modes. Optical spectra were found at each position along the direction of increasing interstice size, and the resonances tend to redshift ...
Source: Plasmonics - January 24, 2020 Category: Biomedical Science Source Type: research

Design of a Frequency Reconfigurable Broadband THz Antenna Based on the Vanadium Dioxide
AbstractIn this article, the design of a frequency reconfigurable broadband THz antenna based on vanadium dioxide (VO2) is investigated. Instead of being fed by the microstrip line directly, a windmill-shaped feeding structure is designed to provide a proximity-coupled feeding method. Many modes with contiguous resonant frequencies can be excited to obtain the wideband performance. The proposed antenna combines gold with metamaterial VO2. Thanks to insulator-metal phase transition characteristic of VO2 at phase transition temperature (68  °C), we can change the length of the resonant branches to realize frequency ...
Source: Plasmonics - January 24, 2020 Category: Biomedical Science Source Type: research

Surface Plasmon Resonance-Based Sensors Using Nano-Ribbons of Graphene and WSe 2
AbstractWe show performance enhancement of surface plasmon resonance (SPR)-based sensors using the nano-ribbons of 2D materials such as graphene and WSe2. 2D material-based structures are useful for refractive index sensing. In this work, conventional graphene-/WSe2-based sensors (in which continuous film of graphene or WSe2 is coated on metal) and graphene/WSe2 nano-ribbon-based sensors are investigated for high quality factors and detection accuracies. Numerical simulations using rigorous coupled wave analysis (RCWA) have been carried out to analyze the sensing performance of the sensors. We show that the possible maximu...
Source: Plasmonics - January 23, 2020 Category: Biomedical Science Source Type: research

Plasmonic Effects of Dual-Metal Nanoparticle Layers for High-Performance Quantum Dot Solar Cells
AbstractTo improve quantum dot solar cell performance, it is crucial to make efficient use of the available incident sunlight to ensure that the absorption is maximized. The ability of metal nanoparticles to concentrate incident sunlight via plasmon resonance can enhance the overall absorption of photovoltaic cells due to the strong confinement that results from near-field coupling or far-field scattering plasmonic effects. Therefore, to simultaneously and synergistically utilize both plasmonic effects, the placement of different plasmonic nanostructures at the appropriate locations in the device structure is also critical...
Source: Plasmonics - January 22, 2020 Category: Biomedical Science Source Type: research

Heat Dissipation of Metal Nanoparticles in the Dipole Approximation
AbstractThe dipolar approximation model that describes the heat delivered by a nanoparticle under continuous light irradiation provides a relation in which the dissipated power is proportional to the extinction cross-section. This relation works fairly well for small particles in which all the energy is absorbed, but fails for larger structures due to the non-negligible power scattered in the free space that does not contribute to heat generation. Here we show that, if we consider the light-induced dipolar field in the calculation of the dissipated power, we recover the proportionality with the absorption cross-section of ...
Source: Plasmonics - January 22, 2020 Category: Biomedical Science Source Type: research

The Surface Plasmon Resonance Polarizing Management in Helical Microstructure Fiber
AbstractSurface plasmon resonance (SPR) is a useful phenomenon in many application fields, such as communication and sensing field. In this paper, for the first time, the SPR phenomenon in helical microstructure fiber coated with Ag (HMFA) is analyzed. Compared with untwisted microstructure fiber, multi-wavelength polarizing filtering performance can be achieved. Tunable filtering wavelength of two orthogonal modes can be achieved by adjusting the twisting rate of HMFA. Besides, at a special twisting rate, the SPR mode with the same order can couple with two orthogonal fundamental modes in HMFA, and the jumping point of th...
Source: Plasmonics - January 21, 2020 Category: Biomedical Science Source Type: research

An Investigation of Efficient Detection of Ultra-Low Concentration of Penicillins in Milk Using AuNPs/PSi Hybrid Structure
AbstractIn this work, porous silicon (PSi) sample was employed to increase the SERS efficiency for rapid detection of penicillins in spiked milk by developing Au nanoparticles (AuNPs)/PSi hybrid structure. SERS was used to study penicillin G and ampicillin residue in milk. The results show that the AuNPs/PSi hybrid structure is very able to detect penicillins residue in milk with an excellent linear relationship and a correlation coefficient (R2 = 1) in the range of 1 × 10−7 mol/L to 1 × 10−9 mol/L. The highest enhancement factors of penicillin G (...
Source: Plasmonics - January 18, 2020 Category: Biomedical Science Source Type: research

Graphene Plasmonic Crystal: Two-Dimensional Gate-Controlled Chemical Potential for Creation of Photonic Bandgap
AbstractA new design of graphene-based plasmonic waveguide is presented and its transmission properties are studied. The transmission channel is such designed that the chemical potential of graphene is periodically changed in two dimensions by application of voltage bias through a patterned substrate. Because of periodicity of structure, it shows a forbidden bandgap at terahertz (THz) frequencies similar to a conventional photonic crystal. The effect of different structure parameters on the rejection band frequency range is numerically studied and the switching function of the proposed waveguide is observed with rejection ...
Source: Plasmonics - January 16, 2020 Category: Biomedical Science Source Type: research

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Source: Plasmonics - January 16, 2020 Category: Biomedical Science Source Type: research

Influence of H 2 Atmosphere Annealing on Plasmonic Properties of Cu-Containing Silica Films Sputtered on Amorphous Silica
AbstractCopper-doped silica films have been deposited on amorphous silica (fused quartz) by magnetron co-sputtering. The resulting films were characterized for copper loading/thickness by Rutherford backscattering spectrometry, and the optical properties were evaluated by absorption and photoluminescence spectroscopies. The films were subjected to thermal treatment under a 5% H2−95% Ar-reducing atmosphere and further evaluated for surface plasmon resonance (SPR) characteristics. In addition, the occurrence of Cu nanoparticles (NPs) was evaluated by transmission electron microscopy. It is indicated that the films have...
Source: Plasmonics - January 13, 2020 Category: Biomedical Science Source Type: research

Design of a Multi-functional Device Based on the Solid-state Plasma: Absorber and Splitter
AbstractWe propose a multi-functional device by using the solid-state plasma, which can be called a plasma metamaterial absorber (PMA). The absorber can get tunable absorption spectrum by exciting different solid-state plasma resonance units. The common absorption frequency region of TE and TM waves can span from 1.7162 to 3.997  THz, whose absorption rate is is than 90%. The simulations also demonstrate that when the excited solid-state plasma resonance units are different, different operating states can be realized. The proposed PMA not only can be seen as an absorber but also can be considered as a reflector or a p...
Source: Plasmonics - January 13, 2020 Category: Biomedical Science Source Type: research

Comparison of Fabrication Methods Based on Nanoimprinting Lithography for Plasmonic Color Filter Fabrication
AbstractThe angle-variable tunable optical filter was strictly fabricated by two strategies of nanoimprint-coupled metal nanopatterning with improved cost-effectiveness and accessibility. The tunable optical properties and the performances of two strategies were experimentally examined and turned out to be well matched to numerical results. Tunable properties are obtained by three factors: size of fabricated Ag nanodisks, incident illumination angle, and fabrication strategies. The resonant extinction peak shifts were identified to show a large increase along with the increase in fabricated Ag disk size and increase in the...
Source: Plasmonics - January 10, 2020 Category: Biomedical Science Source Type: research

Optimal Aspect Ratio and Excitation Spectral Region of LSPR Sensors Using Individual Au Dimmeric Nanoplates
AbstractBoth the excitation wavelength and aspect ratioAR are key parameters controlling the refractive index sensitivity performances of plasmonic sensors of individual Au nanoplate dimmers. In this work, the refractive index sensitivity factorS and figure of meritFOM of individual Au dimmeric nanoplate sensors with different plate cross-sections were investigated numerically as functions ofAR and their resonant wavelength of dipolar localized surface plasmons. Their optimalFOM and corresponding optimalAR and excitation spectral region for plasmonic sensing are predicted simultaneously. The effects of the plate cross-sect...
Source: Plasmonics - January 10, 2020 Category: Biomedical Science Source Type: research