Here, full-wave analysis and design of an electrically tunable optical fractional-order temporal differentiator (DIFF) based on an ultra-compact microring resonator (MRR) has been presented. Electrical tunability has been realized through free carrier dispersion (FCD) effect in the resonator with P-I-N and P-N junctions. The first-order optical DIFF is realized based on the critically-coupled resonator

Thanks to the combination of molybdenum disulfide, an emerging two-dimensional material, with spherical metal nanoparticles monomers (Au, Ag), homodimers (Au-Au, Ag-Ag) and heterodimers (Au-Ag), all peaks of Local Surface Plasmon Resonance (LSPR) are broadened. Detailed analyses are conducted regarding the effects of molybdenum disulfide on LSPR of different structures from the view point of different

Effects of both metamaterial inclusion and lack of inversion symmetry on the localized modes in one-dimensional photonic heterostructures under normal incidence are investigated. Each structure consists of two semi-infinite photonic crystals separated by an interface or by several layers. A general condition for light localization between semi-infinite crystals is given by parallelism between two-dimensional

This paper reports, for the first time to the best of our knowledge, the design of a compact three-mode converter/(de)multiplexer (DE/MUX) based on a 3 × 3 subwavelength grating (SWG) multimode interference (MMI) coupler. The device uses a π/2 phase shifter and an asymmetric tri-junction coupler built in a silicon/silicon-on-insulator (SOI) platform. The inherent dispersion and anisotropy properties

Resonant plasmonic nanostructures have attracted much attention due to their exotic optical properties. In this work, we numerically investigate single- and dual-gap ring structures, respectively, and they can be used for refractive index sensing by exciting the gap plasmon mode with sharp resonance spectra. The dual-gap ring plasmonic sensor shows the dual-channel properties and the corresponding

This paper presents ultrathin multi-focusing metalenses that can produce several independent focusing spots, useful in imaging for light flow redistribution, even asymmetrical into many focal spots. The proposed design includes quadrangular frustum pyramids serving as individually tuned nanoantennas; their structure can be modified, facilitating wave-phase retardation tuning. Combining the propagation

We design and estimate the performance of an integrated Bragg grating (IBG) filter that has Si3N4-filled periodic grooves on a silicon strip waveguide. Also, the entire IBG filter is covered with Si3N4 cladding. The refractive index variation along the length of the filter is achieved by the periodic Si3N4-filled corrugations. We consider different geometries of grooves that can be other than the ideal

We propose a photonic crystal circulator based on quadrupole resonance of a magnetized ferrite cylinder. This device consists of a T-junction composed by three waveguides in a two-dimensional photonic crystal with square lattice. The ferrite cylinder is placed in the center of the T-junction. The scattering matrix, analytical model and the numerically calculated frequency characteristics of the circulator

We study the resonances in transmission of a subwavelength dielectric lossless structure, periodic in one direction and infinite in the orthogonal (i.e. the effectively 2D problem). We are interested in the case of an encapsulated grid, deeply embedded into an optically-homogeneous surrounding medium. In the case, even a thin periodic structure, characterized by a positive relative excess of the refractive

In this paper, we design a novel photonic crystal fiber (PCF) chemical sensor in terahertz region wherein the cladding structure is made of a dual steering-wheel (DSW) shape of large non-circular air-hole. In this PCF, rectangular structured air holes are introduced in the core, which, in turn, is filled with any of the analytes, namely, water, ethanol and benzene. We use the full-vectorial finite

Recently a hypothesis explaining the non-resonant mechanism of subwavelength imaging granted by a dielectric microsphere has been suggested. In accordance to the hypothesis, the far-field image of a subwavelength scatterer strongly coupled to a microsphere by near fields is offered by the scatterer polarization normal to the sphere surface. The radiation of a closely located normally polarized dipole

The Fano resonance with a distinctive ultra-sharp, asymmetric line shape and high quality factor, is a widely occurring phenomena, that has a large variety of optical, plasmonic and microwave manifestations. In this paper, we explore the characteristic robustness of a Fano resonance mode, which is topologically protected by engineering a band inversion, induced by breaking the mirror symmetry of a

In this work, a 3-layer cross copper grating structure, which is the basic structure in semiconductor processing technology, is simulated by the rigorous coupled wave analysis (RCWA) and the finite element method (FEM). The reflection spectrum shows a reflection dip in the infrared frequencies. The electric field distributions indicate that the dip is caused by the 1st order bonding localized surface

In this study, we propose a black phosphorus (BP)/waveguide terahertz plasmonic sensing structure comprising vertically stacked crystal quartz, polymethylpentene (TPX), BP, crystal quartz, and TPX layers on a germanium prism. Sharp Fano-type resonance is induced by strong coupling between the surface plasmon polariton and planar waveguide modes, and it generates imaging sensitivity of up to 9.978 × 103

Fiber optic surface plasmon resonance (SPR) sensors are the miniaturized alternative to the conventional prism based SPR platform. Among its various types, microstructure optical fiber (MOF) sensors have recently gained immense popularity, owing to the possibility of a controlled or enhanced interaction between the guided light and sensing analyte. In this review, we discuss about the hollow MOFs utilized

In this contribution, a new optimized photonic bandgap (PBG) based antenna is proposed for broadband applications of the terahertz spectrum. First, the reference antenna is designed and optimized using a parametric study to operate at the resonance frequency of 0.3 THz. Then, the optimization is performed with a novel technique, called segmented objects technique (SOT), to guide the optimization of

In this paper, we design a silicon-core photonic crystal fiber (PCF) composed of MgF2 background material to generate supercontinuum spectra in the near- and mid-infrared wavelength ranges. The linear properties of the PCF, including effective index, group velocity dispersion, loss, and effective area, as well as the nonlinear parameter, are calculated for several core radii. We show that by choosing

Nowadays, most of the on-chip plasmonic single-photon sources emit an unpolarized stream of single photons that demand a subsequent polarizer stage in a practical quantum cryptography system. In this paper, we numerically demonstrated the coupling of the light emitted from a quantum emitter (QE) at 700 nm wavelength to the propagation mode supported by an on-chip hybrid plasmonic waveguide (HPW) polarization

Metamaterial absorbers with excellent absorption properties and real-time tunability are desirable for practical applications. In this paper, we design and numerically investigate a polarization insensitive wide-angle metamaterial absorber with tunable absorption strength formed by finite-length symmetric metallic plates and graphene sheet. This structure achieves a near perfect absorption, and remains

Zinc-doped manganese ferrites synthesized by chemical co-precipitation technique showed significant linear and nonlinear optical properties and have been utilized to realize optoelectronic device applications. Mn1−xZnxFe2O4 (0 ≤ x ≤ 0.25) nanoparticles were characterized by various spectroscopic and microscopic techniques along with Z-scan studies. The formation of a single phase cubic spinel structure

In this paper, an all-optical 4-to-1 digital multiplexer is proposed based on photonic crystals. A digital multiplexer is a combinational logic device allowing control of which one of four input ports can be connected to the output port. For performing this functionality, in addition to the input and output ports, the multiplexer also has two control ports. Nonlinear ring resonators are used to design

Laser-crystallization processes to convert amorphous-Si to poly-crystalline-Si are attracted considerable attention owing to their industrial applications, such as in active matrix organic light-emitting diode displays (AMOLEDs) and photovoltaic devices and general scientific interest. Multiple irradiation sequences were conducted with a 355 nm UV laser on amorphous-Si (40, 50, and 60 nm)/oxide(300 nm)

A broadband reflectarray antenna is proposed for operating at THz frequencies. An array of single-layer elements is composed of gold patches printed on a grounded cyclic olefin copolymer (COC) substrate. The elements are designed to have a smooth and linear phase reflection curve versus element positions. A random hill-climbing (RHC) optimization algorithm is applied to obtain the broadest bandwidth

We propose and demonstrate a polarization splitter and rotator (PSR) operating in the range of 1530–1590 nm, built on the SOI platform and based on a new bow tie converter TM0-to-TE1. Comparing with other compact (<100 µm length) state-of-the-art photonic integrated devices, the proposed device exhibits simultaneously the lowest crosstalk and penalty to fabrication errors, paving the way for high-volume

The non-linear rectification and generation of the second and third harmonic of a realistic single-electron Ga1−yAlyAs/GaAs/Ga1−xAlxAs V-groove quantum wire are calculated. The effects of the V-groove geometrical and physical parameters, such as the inter-sidewall angle, the thickness of the crescent, the position of the pinch-offs, the temperature of the sample, and the aluminum concentration on the

We have theoretically investigated the nonreciprocal surface states created at the interface between the semi-infinite one-dimensional magneto-optic photonic crystal in Voigt configuration and air in the presence of monolayer graphene as a cap layer, using the transfer matrix method. The modification of surface states was studied by changing the Fermi energy of the graphene sheet. The results indicate

A new type of surface plasmon resonance biosensor based on inverted graded index optical fiber is presented. To allow the exciting of the surface plasmons, the cladding is removed and a thin film of gold is coated on the inverted graded index core at this region. This sensor can measure the refractive index (RI) of biomaterials in the range of 1.36–1.48. The simulation results show that the proposed

Diagnosis of diseases through exhalation is a new, noninvasive method. In this study, a new photonic crystal fiber (PCF) has been proposed for detecting ammonia gas in breath. The spectroscopy system contains a tunable laser source, a monochromator that sets the wavelength at the absorption line of ammonia gas, a PCF used as a cell gas, a detector, and a computer to monitor and show the results. The

We report the creation of Ge2Sb2Te5 metasurfaces on sapphire substrates by the ablation method and the study of their structural properties by scanning electron microscopy (SEM), atomic force microscopy (AFM), and optical diffraction. The main emphasis is on the optical technique, which boils down to obtaining bright Laue diffraction patterns on a screen, observing them with the naked eye, and analyzing

Nowadays, optical data transmission systems are significantly involved in telecommunication networks. Particularly, hundreds of data channels can be sent concurrently over a single optical fiber through dense wavelength division multiplexing (DWDM) and optical time division multiplexing technologies. Nevertheless, dispersion imposes main limitations for having high capacity systems with high transmission

In this paper, a highly efficient multiband optimized slotted pentagonal terahertz patch antenna and its 2 × 2 multi-input multi-output (MIMO) planar array is proposed for multiple terahertz (THz) applications like high-speed indoor communications, explosive detections, arms detection, medical imaging, pharmaceutical analysis, and industrial inspections, etc. Here, the proposed patch antenna is developed

Herein, we presented a novel design of polarization beam splitter (PBS) based on the integration of heterostructure 2D- Photonic crystals (PhCs). Two PhC structures, namely PhC-type 1 and PhC-type 2, with different transmission characteristics are proposed. The first type of PhC is composed of a 2D-periodic array of circular air holes embedded in silicon substrate which facilitates the propagation

In this paper, a highly sensitive plasmonic refractive index (RI) sensor based on photonic crystal fiber (PCF) is proposed. Silver (Ag) is used as plasmonic material and tantalum pentoxide (Ta2O5), high RI material, is used as an overlayer over the silver thin film. The sensor performance is realized using surface plasmon resonance (SPR) phenomenon. The effect of tantalum pentoxide overlayer thickness

A novel square shaped air hole based photonic crystal fiber (PCF) is proposed with three symmetrical rectangular slots in the core region. A highly nonlinear material Gallium phosphide (GaP) is doped in the middle rectangular slot to achieve high nonlinearity and birefringence as well. Finite element method (FEM) is used for numerical investigation of the structure. Different optical parameters of

The design, optimization, and analysis of two-dimensional metal-assisted guided mode resonance (MAGMR) based sensing structures have been presented focusing on the visible range of operation. The study has been conducted for square and hexagonal lattice geometries and the sensing properties and performance of the MAMGR structures have been compared with the traditional guided-mode resonance (GMR) structures

This study presents a hexagonal array of submicron hollow veins covered with a high-refractive-index (n) ceramic layer for extracting and steering light trapped in organic light-emitting diodes (LEDs). The hollow veins sustained by an ultrathin (35 nm in thickness) alumina wall were fabricated on a glass substrate by sequentially using nanoimprinting lithography, atomic layer deposition, and calcination

Thin films of photonic crystals with inverse opal structure were prepared from opal-type templates, using photocurable resin polymerisation. Different techniques for neatly incorporating gold nanoparticles (NPs) into inverse opal films, based on multiple infiltration of water-ethanol solution of gold NPs, were proposed. In a number of cases, a sharp deepening of the transmittance dip in the region

I describe three ways that the spatial properties of a wave propagation medium can cause dispersion, and propose that they should form the basics for correctly understanding and naming phenomena described as “spatial dispersion”. In particular, I emphasise the specific spatial properties which generate the resulting dispersive – i.e. spatially dispersive – behaviour. The properties are geometry, structure

Using e-beam lithography and reactive ion beam etching of a 120 nm amorphous silicon film, we fabricate a 30-µm spiral metalens that has a very short focal length that is equal to the incident 633 nm wavelength (numerical aperture about 1) and is composed of 16-sectored subwavelength binary gratings with a 220 nm period. Its unique feature is that the metalens generates a left-hand circularly polarized

Surface plasmon polaritons can be efficiently excited using attenuated total internal reflection techniques or with diffraction gratings. An alternative way actively studied in recent years is the use of nanoantennas. Here, we show that the amplitude of surface plasmon polariton excited by a nanoantenna can be found analytically using a well-known method for calculation of guided-mode amplitudes in

Generation of a photonic nanojet with a slightly subwavelength waist at the back side of a dielectric microsphere or microcylinder impinged by a plane wave has recently shown that the near-field effects may hold not only inside the dielectric microparticle, but also outside it. In this paper we explain how to drastically increase the external near-field effect. For it one has to replace a plane wave

We theoretically investigated the localization and switching properties of surface waves that appear at the interface between the homogeneous medium and a semi-infinite one-dimensional photonic crystal in the presence of chiral metamaterial as a cap layer, using the transfer matrix method. The one-dimensional photonic crystal is made of alternating layers of right-handed and dispersive left-handed

In this work, a high Q-factor photonic crystal microring resonator (PC-MRR) based pressure sensor is reported. This sensor is designed based on SOI technology. The modelling and analysis of integrated optical (IO) resonator and mechanical diaphragm are carried out by using the Finite Element Method (FEM) and the Finite-Difference Time-Domain (FDTD) method respectively. The sensor consists of IO hexagonal

In magnetic resonance imaging, a birdcage coil is the most commonly used volumetric resonator creating a highly homogeneous radiofrequency magnetic field in a conductive sample. An artificial magnetic radiofrequency shield was recently shown to improve the magnetic field amplitude per unit power (transmit efficiency) of a preclinical birdcage coil by reducing the intrinsic losses in the coil and increasing

To realize wavelength division multiplexing for high-capacity optical communications, we theoretically investigate the properties of a photonic crystal waveguide structure in which a row of air holes is displaced by a/2 (a is the lattice constant). We calculate transmission loss and coupling efficiency to circular defect cavities of this waveguide structure, which we call an orthogonal lattice waveguide

Noble metal material, size, period and position are key parameters to affect optical absorption property of perovskite thin film, which was numerically investigated in this paper by finite element method. It demonstrates that Al nanoparticles show larger enhancement ability of light absorption than that of Au and Ag under AM1.5 illumination with the same geometry parameter. The light absorption enhancement

One-dimensional structures of non-Hermitian plasmonic metallic nanospheres are studied in this paper. For a single sphere, solving Maxwell's equations results in quasi-stationary eigenmodes with complex quantized frequencies. Coupled mode theory is employed in order to study more complex structures. The similarity between the coupled mode equations and the effective non-Hermitian Hamiltonians governing

In this article, we propose the design and analysis of all-dielectric metasurface based tunable optical modulator. The metasurface structure consists of split silicon arcs mounted over the indium tin oxide layer and the silica substrate. The nematic liquid crystal is used for tuning the Fano resonance peak of the metasurface and is filled between two indium tin oxide layers. The numerical investigation

In this paper we aim to propose and design an all optical analog to digital converter for generating 2-bit Gray codes from the optical intensity of the input signal. Two nonlinear resonant rings will be used for realizing the proposed structure. These nonlinear resonators should be designed such that they can drop optical waves at different optical intensity ranges. The nonlinear resonators will be

We report on tellurium nanorods as a new type of saturable absorber (SA)-induced four-wave-mixing to construct an all-fiber multi-wavelength passively Q-switched erbium-doped-fiber laser. This proposed material is prepared via a green method of nanorod synthesis. The results show that the SA device simultaneously generates seven wavelengths within 1592.4–1599.6 nm waveband and mode spacing of 1.2 nm

A hot-spot of high local field can be created between two closely placed metal nanoparticles and by irradiating them with an appropriate wavelength and polarization of incident light. The strength of the field at the gap between the particles is expected to get enhanced by several orders of magnitude higher than that of the applied field. Placing a semiconductor quantum dot or an analyte molecule at

We investigate a high-sensitivity plasmonic sensor that uses a hexagonal nanorod array metasurface with for identifying malignant hepatic metastases from healthy liver cells. This designed plasmonic metasurface has some advantages such as nanoscale dimensions, a high figure of merit and sensitivity to the refractive index, and insensitivity to the incident angle for 0° to 60°. With the 3D finite-difference

A three-dimensional electromagnetic field model has been developed to study the photon capture properties of gradient band-gap AlxGa1-xN nanomaterials with built-in electric field using COMSOL Multiphysics commercial software based on finite element numerical simulation. Based on the phototrapping mechanism and the concept of radial mode resonance absorption, we studied AlxGa1-xN nanomaterials with

The design, analysis, and simulation of a 1 × 2 decoder based on self-collimated beams was the aim of this work. The proposed structure consists of two-dimensional (2D) photonic crystals with their silicon rods in air. The device, of a relatively simple structure with a footprint of 228.71 μm2, comprises two inputs (I and Iref) and three outputs (Q1, Q2, and QI). It, furthermore, contains two beam