- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Polarization independent quad-bandpass frequency selective surfaces with wide-band ratio
摘要： A single layer polarization independent quad-bandpass frequency selective surface (FSS) with wide-band ratio is demonstrated theoretically as well as experimentally. The proposed structure passes four frequency bands with wide band ratio. The proposed FSS design is implemented by incorporating alternate arrangement of four units which are rotated 90° clockwise to form a unit cell of metal over a FR4 substrate. The geometrical dimensions of proposed unit cell are optimized and arranged in such a way that the structure possesses the quad bandpass characteristic and aspect dimensions of one unit is 0.11λ × 0.11λ with respect to first resonant frequency. This FSS provides stable response for different angle of incidence in transverse electric (TE) mode and transverse magnetic (TM) mode. To validate the results proposed FSS array has been fabricated and measured in free space environment. The measured results are in good agreement with the simulated results. Excellent stability is also observed for different incident angle.
关键词： quad bandpass,polarization independent,frequency selective surface,band ratio
更新于2025-09-23 15:23:52
-
Polarization-independent hybrid plasmonic coupler based on T-shaped slot waveguide
摘要： In this paper, a novel polarization-independent hybrid plasmonic coupler based on a T-shaped slot waveguide is proposed and investigated by numerical simulations using the finite element method. The structure supports both the TE-polarized slot waveguide mode and the TM-polarized plasmonic mode, offering a greater possibility to achieve the polarization-independent operation. The simulation results show that with proper structural parameters, the waveguide coupler with high extinction ratios of 31.2 dB (TE) and 30 dB (TM) and low insertion losses of 0.38 dB (TE) and 2.04 dB (TM) can be achieved at a telecommunication wavelength of 1550 nm. An investigation of the influence of structural perturbations indicates that the proposed coupler also has a good tolerance to fabrication errors. The proposed structure has potential applications in the field of subwavelength integrated photonic circuits.
关键词： polarization-independent,hybrid plasmonic coupler,finite element method,T-shaped slot waveguide,photonic integrated circuits
更新于2025-09-23 15:21:01
-
Polarization-Independent Reconfigurable Graphene Gas Sensor Using Crescent Plasmonic Antenna
摘要： A polarization-independent gas sensor based on crescent plasmonic dipole antenna loaded with graphene monolayer is introduced in this paper for environment monitoring applications. Single, dual, and four arms crescent dipoles are designed, analyzed and investigated. The proposed gas sensor has reconfigurable absorption characteristics in the wavelength range from 900 to 1600 nm which covers the different gases responses. A parametric study on the effect of the sensor dimensions and polarization of the illuminated waves on the total absorption of different gases is investigated. A graphene monolayer is used to enhance the gas molecule absorption in its unbiased state. An enhancement of the total absorption cross section (ACS) values for n = 1.4 is 1.028 × 105 nm2 for the unloaded sensor case and is 1.77 × 105 for the graphene loaded sensor case. The unloaded graphene sensor sensitivity is 630 nm/RIU, and for the graphene loaded case is 677.5 nm/RIU. Dual-polarized crescent dipole consists of two orthogonal arms is designed to maintain the same sensitivity for x- and y-polarized E-field illumination. A polarization independent gas sensor consists of four crescents dipole arms rotated with 45° is explained. An enhancement of gas absorption is achieved by using a sensor array of four-arm dipole sensor. Different array sizes loaded with graphene monolayer are investigated. The total ACS peak value is 7.84 × 106 nm2 for 6 × 6 dipole array is obtained.
关键词： Gas sensor,Graphene,Sensing antenna,Polarization independent
更新于2025-09-19 17:13:59
-
[IEEE 2019 International Conference on Electrical, Communication, and Computer Engineering (ICECCE) - Swat, Pakistan (2019.7.24-2019.7.25)] 2019 International Conference on Electrical, Communication, and Computer Engineering (ICECCE) - Nanoplasmonic Quasi Crystal Metascreen Optimized for Efficient Light Absorption
摘要： A metascreen absorber composed of plasmonic nanodisk array is used to absorb incident radiation at optical frequencies. The conventional Nobel metals such as gold and silver are considered as best plasmonic materials to couple incident light to surface plasmons modes. However, it is found that alternative plasmonic materials such as copper (Cu) offers optimized absorption characteristics. Copper nanodisk absorber offers a broad range of optical absorption ranging from 400 nm – 1500 nm wavelength. In addition, it is found that the light absorption bandwidth can be signi?cantly enhanced or near perfect absorption can be reached if plasmonic nanodisks are arranged in quasi-crystal con?guration. The proposed quasicrystal based metascreen absorber offers potential applications for light energy harvesting and optical sensing applications.
关键词： Salisbury screen absorber,polarization independent,metasurface,terahertz frequencies,broadband absorption
更新于2025-09-16 10:30:52
-
Tunable and Polarization-Independent Plasmon-Induced Transparency in a Fourfold Symmetric Metal-Graphene Terahertz Metamaterial
摘要： The introduction of graphene into metamaterials allows for more flexible and convenient control of electromagnetic waves. In this paper, one simple plasmon-induced transparency (PIT) structure with tunability and polarization independence is investigated in the terahertz (THz) regime. The simulation results indicate that the transparent window can be manipulated in a wide range and even switched off by merely changing the Fermi energy of graphene. By continuously altering the resonance intensity of the dark resonator using the graphene, the PIT resonance can be actively manipulated. The behavior can be elucidated by the classical coupled two-particle model, which corresponds well to the simulation results. Owing to the fourfold symmetric structure, the proposed PIT device exhibits polarization-independent characteristics. This work provides design guidance for metal-graphene THz modulators.
关键词： polarization-independent,metamaterial,plasmon-induced transparency,graphene
更新于2025-09-11 14:15:04
-
Embossing Reactive Mesogens: A Facile Approach to Polarization-Independent Liquid Crystal Devices
摘要： Reactive mesogens (RMs) are used in a wide variety of applications, from retardation plates for organic light-emitting display screens, liquid crystal phase stabilization, optical or electrically active elastomers to novel optic components. They can be processed as standard liquid crystals and subsequently polymerized to stabilize both shape and anisotropic properties. However, creating complex shapes while maintaining good alignment of the RM optical axis can be a challenge. In the present work, embossing is used to replicate a wide variety of RM structures in several electro-optic devices. A novel device geometry is proposed where a polarization-independent lens is formed by opposing birefringent Fresnel zone plates embossed in aligned RM. The RM forms the optical elements and alignment layers for an index-matched liquid crystal, arranged to produce the twisted nematic configuration. Low voltages switch the device between nonfocusing and focusing states. After characterizing lens efficiency and beam properties, the method is used to fabricate a switchable multilevel Fresnel zone plate with optical efficiencies beyond 50%, and theoretically able to produce polarization-independent lenses with efficiencies approaching 100% from a single structure. Finally, manufactured polarization-independent gratings and microlens arrays are presented using the method to illustrate the wide range of applicability.
关键词： liquid crystals,embossing,reactive mesogens,polarization-independent devices
更新于2025-09-10 09:29:36
-
Polarization-independent and super broadband flat lens composed of graded index annular photonic crystals
摘要： In this paper, we propose two types of all-dielectric polarization-independent graded index annular flat lens with a wide operating frequency range. The lenses are composed of two-dimensional triangular and square lattice photonic crystals with circular silica (SiO2) rods in the air. We assume in both square and triangular structures, the lenses are obtained by making air holes within each dielectric rod and we consider that the outer radius of the created annular rods are maintained constant while the size of the inner air holes varies along the transverse direction whose the air holes variation follow linear and parabolic function. The graded structures are made in such a way that the modulus of the refractive index is biggest at the center and decreases toward the edges. The optical properties and the physical background of the polarization-independent focusing mechanism are studied in frequency and spatial domains, using plane wave expansion and finite-difference time-domain methods. Our numerical results show that, through an appropriate set of design, the deigned lenses are able to focus the light regardless of polarization for a wide frequency range into approximately same focal length in which difference between focal distance of TE and TM polarization modes stays below λ/4. Compared to previously polarization-independent designed photonic crystal based lenses, our proposed structures work under much wider frequency range. Also, in contrast with most of the graded structures, our graded lens are made without altering the lattice constant along optical axis or transverse to optical axis. Moreover, the design approach is restricted to use of silica and non-use of more complicate materials such as liquid crystals, plasma, and the like. Thus, the designed systems can be constructed easier relative to the previously designed lenses.
关键词： Graded index annular photonic crystals,Optical beam focusing,broadband frequency lens,Polarization-independent lens
更新于2025-09-10 09:29:36
-
Two dimensional sinusoidal Ag nanograting exhibits polarization-independent surface-enhanced Raman spectroscopy and its surface plasmon polariton and localized surface plasmon coupling with Au nanospheres colloids
摘要： A reproducible surface‐enhanced Raman scattering (SERS) substrate based on two dimensional (2D) sinusoidal Ag nanograting is presented. This SERS substrate with large area can be easily fabricated by maskless laser interference photolithography. The potential SERS polarization‐independent performance of 2D sinusoidal Ag nanograting is deduced by finite difference time domain and demonstrated by SERS detection experiments. A double‐enhanced Raman scattering (DERS) substrate by coupling 2D sinusoidal Ag nanograting with Au nanospheres colloids is created. With the optimal DERS substrate, SERS enhancement factor can be 10 orders of magnitude as possible. The DERS substrate was fabricated and an extra SERS effect was proved by experiments. This DERS substrate will be fabricated in a microfluidics‐based sensor in the next work and used for in situ, real‐time, continuous monitoring of trace water soluble gas‐phase or airborne agents, such as trace explosives in air.
关键词： surface plasmon polaritons,surface enhanced Raman scattering,localized surface plasmons,two dimensional sinusoidal nanograting,polarization‐independent
更新于2025-09-10 09:29:36
-
A NOVEL POLARIZATION INDEPENDENT CHIPLESS RFID TAG USING MULTIPLE RESONATORS
摘要： A novel polarization independent RFID tag employing multiple resonators is proposed. The prototype of the tag is fabricated on a low-cost substrate of dielectric constant 4.4 and loss tangent 0.02. Designing a reader for chipless RFID is a hard task since both the polarization and operating frequency agility have to be implemented. The new tag design proposed in this paper is polarization independent, making the design of the reader easier. A prototype of a 3 bit data encoded tag is demonstrated using single structure which can be extended to any order by cascading. This new design is experimentally validated in the frequency domain using monostatic measurement with magnitude response to decode the information.
关键词： polarization independent,multiple resonators,low-cost substrate,chipless RFID tag,frequency domain
更新于2025-09-09 09:28:46
-
Polarization-Independent Narrowband Near-Perfect Absorption Based on One-Dimension Embedded Aluminum Grating
摘要： In the past, the polarization-insensitive absorption is realized mainly employing the two-dimensional periodic structure of fourfold rotational symmetry, which greatly increases the manufacturing complexity and cost. Here, we present the numerical design of a polarization-independent near-perfect absorber incorporating one-dimensional embedded aluminum grating. The absorption peaks near 99% at 520-nm wavelength for different polarization angles are achieved. The underlying mechanism associated with the resonance is attributed to the magnetic polariton resonance and the cavity-mode resonance for TM and TE polarization, respectively, and further explained by the inductor-capacitor circuit model and the eigen equation of cavity mode. Furthermore, the effects of geometrical parameters of the nano-cavity on the absorption performance are discussed. The proposed structure may provide a new way to achieve polarization-independent absorption with one-dimensional meta-surface, which has broad applications in plasmonic sensors, photo-detectors, and so on.
关键词： Grating,Resonance,Polarization-independent,Absorption,Narrowband
更新于2025-09-04 15:30:14