Arash Sabatyan

Urmia University · Department of Physics

The combination of a grating as a periodic object and a Fresnel zone plate with a quasi-periodic structure leads us to propose some novel array generator elements. It is shown that diffraction performance of the proposed element depends on the grating structure, so that the diffraction performance may efficiently be increased if the grating is repl...

We present a novel technique based on linear zone plate (LZP) by which linear singularities regarded as fractional vortex dipoles are efficiently generated. Our approach requires applying spiral phase to a LZP, so fractional vortex dipoles are then acquired. By also implementing transverse phase shift to the spiral LZP, we are able to equally divid...

We aim here to present two models of spiral zone plate-based diffractive elements. To this end, it is shown that by a given combination of two spiral zone plates (SZPs) with opposite-signed charge strengths some novel elements are born whose phase structures are azimuthally shifted. Therefore, they are named azimuthal phase-shifted zone plates. Gen...

A multi-purpose diffractive element with unique possibilities in generating a multi-spiral intensity pattern is reported. The element is created by the superposition of an inwardly and outwardly radial phase-shifted zone plate. It is demonstrated that a focused multi-spiral beam is acquired so the number of spiral arms, as well as spiral turns, is...

Herein, we present a so-called multiregion spiral square zone plate (MRSSZP), in which a spiral square zone plate is divided into a few regions, so that every region is composed of Fresnel zones, and the first zone of a given region is the same as the last zone of the previous region from a transmission point of view. We show that an MRSSZP can gen...

This paper presents a novel approach for generating structured light using a diffractive beam-shaping element that can generate multiple beams with distinct spatial structures in the focal plane. The element is constructed by restructuring a spiral zone plate with fork gratings, providing a tunable and controllable means for generating structured l...

This paper showcases a novel composite diffractive element that can be finely tuned to generate a myriad of stunning beam patterns and structures. Specifically, we have redesigned the spiral zone plate by incorporating a complex sinusoidal grating into its structure, which has considerably expanded the range of effective parameters available to eng...

By taking advantage of spiral petal-like zone plates, we have recently demonstrated that a spiral element’s geometric shape impacts its charge. Keeping it in mind, we aim to control the topological charge of a vortex using phase modification of a spiral zone plate without transforming its geometrical shape. This is achieved by apodizing a spiral zo...

This work studies the unique behavior of spiral checkerboard zone plates under plane wave illumination. The element is constructed by superimposing two orthogonal helical linear zone plates. Based on their topological charge, various structured beams are generated whose structures display fascinating dynamics. Structure transforming, vortex pair pr...

Abstract- This study introduces and demonstrates the superposition of optical vortex beams. Optical vortices are attracting more and more attention because they carry orbital angular momentum (OAM) associated with the phase distribution of exp(i𝜄𝜑), where 𝜄 is the topological charge. An important characteristic of an optical vortices is topological...

superposition

Herein, we are about to introduce a novel, reliable and straightforward method to create controllable dark lines employing an azimuthal square zone plate. As a matter of fact, this diffractive element is a square zone plate whose zones are phase-shifted azimuthally. As we illustrate, one way to construct it is combining a square zone plate and radi...

In this paper, The superposition of optical vortex beams will be examined. In order to produce, optical vortex beams, we used of Fresnel spiral regional plates and superposition of optical vortex beams, we used Fresnel spiral zone plates and studied the overlap of the optical vortex beams resulting from the spiral fresnel zonal plates inside the fo...

Herein, we are about to introduce a novel, reliable and straightforward method to create controllable dark lines employing an azimuthal square zone plate. As a matter of fact, this diffractive element is a square zone plate whose zones are phase-shifted azimuthally. As we illustrate, one way to construct it is combining a square zone plate and radi...

We aim to introduce and study a composite spiral photon sieve that is a photon sieve made of two independent and individual segments. Each segment has its characteristics, including hole density, diameter, and the number of spiral arms. We demonstrate that the element capable of producing a variety of optical vortex whose shape and structure is a f...

Herein, the coherence combination is simply the sum of two ormore diffractive elements to achieve a novel diffractive element with its uniquebehavior. Concerning this concept, we aim to demonstrate how a long-depthbifocal diffractive lens is emerged by a combination of two radial phase-shiftedFresnel zone plate. Besides, we will also show that the...

In this work, we present a technique based on a helically modulated petal zone plate through which topological charge is handled. Basically, in this case, we are dealing with two kinds of phase change, the first one is a sinusoidally azimuthal phase change and the second one is helically changing of the phase. We have shown that the total topologic...

Herein, we propose a multi-region spiral photon sieve in which each region has its features like focus and topological charge. Because the segmentation offers us to consider each region as an individual spiral photon sieve to manage the focusing behavior of the element. Accordingly, we have considered a four-region element so any region has its mai...

The overall objective of this research is to check the abilities of two non-destructive techniques, the digital imaging (DI) and laser light backscattering imaging (LLBI), on detection of α-solanine toxicant in potatoes. Potato samples were classified in healthy and toxic categories based on the amount of α-solanine. For quantifying α-solanine in p...

We aim here to show that azimuthal structuring of the optical beam may be realized by apodizing a spiral zone plate using an azimuthal-modulated Bessel function. Furthermore, we demonstrate that the azimuthal modulation of a Bessel beam may cause its transmittance to take negative values in azimuth. Accordingly, when a diffractive element (herein,...

We aim here to show that azimuthal structuring of the optical beam may be realized by apodizing spiral zone plate using an azimuthal modulated Bessel function. We demonstrate that the azimuthal modulation of a Bessel beam may cause its transmittance to take negative values in azimuth. Accordingly, when a diffractive element (herein spiral zone plat...

This study introduces and demonstrates the diffractive feature of a bi-segment spiral zone plate, so that each segment has its own width, topological charge, and radial phase shift. We show that the focusing behavior of this element depends strongly on these parameters. We demonstrate how these features can handle the focused intensity and structur...

we introduce a novel diffraction element for generating any desired arrays of the vortex and perfect vortex beam. The method is based on combining radially phase shifted spiral zone plate with different gratings. We show that the element has a great potential in generating a variety of arrays with desired vortex ring radius and topological charges....

We demonstrate structured spiral hyperbolic zone plate which is able to generate a chain of fractional vortex dipoles. The element is created by superimposition of two perpendicular hyperbolic zone plates in horizontal and vertical directions and its phase structure is then modified by adding a azimuthal characteristics factor. By setting different...

The apodizing spiral zone plate with Bessel functions shows interesting focusing behavior in the generation of a variety of uni- and multiannular (specially biannular) azimuthal and annular vortex beams carrying screw and annular phase dislocation. Theoretically, studies utilizing scalar diffraction integrals show generation of hypergeometric F 2 1...

Apodizing spiral zone plate with Bessel functions shows interesting focusing behavior in a generation a variety of-of uni and multiannular (specially biannular), azimuthal and annular vortex beam carrying screw and annular phase dislocation. Theoretically studies utilizing scalar diffraction integral show generation of hypergeometric $_2F_1(a,b,c;x...

We demonstrate that by dividing a Fresnel zone plate into a few regions having different periods in the s = r 2 coordinate, then replacing the clear zones by a given distribution of pinholes, a so-called modified photon sieve is constructed. The first feature of the element is to increase its diameter without worrying about its feature size as the...

High efficiency grating-based diffractive elements were previously proposed in order to generate desired arrays of various optical beams. The elements enable us to generate a diversity of arrays of optical beams in desired shapes, so that the arrays produced by the method are homogeneous, uniform and lacking of unwanted higher diffraction orders. I...

Unique linear structured light beams carrying fractional vortex dipoles in the shape of either a transverse elliptical beam or a transverse bottle-like beam are presented and studied. These beams are generated using a novel diffractive element produced by a given combination of two phase-shifted spiral linear zone plates with equal but opposite hel...

This study introduces and examines the diffraction properties of a so-called petal-like zone plate, which comprises Fresnel zones analogous to petals. We show that the focusing behavior of this novel type of zone plate depends on the number of petals included in the element. For a small value of the petal frequency, we observe star-like diffraction...

This patent introduces a novel diffractive lens named as petal-like zone plate which comprises Fresnel zones analogous to petals. The focusing behavior of this novel type of zone plate depends on the number of the petals included in the element. In the sense that for a small value of the petal frequency star-like diffraction patterns are observed a...

Structuring plane light beam into spiral beam by making use of spiral phase shifted zone plate

We aim here to present a novel Fresnel zone plate- based element which is referred to as multi-twisted zone plate. This element is a zone plate whose phase structure is multi-spirally shifted. It is made of the binary combination of two radial phase shifted spiral zone plate. Given the produced structure, two various-charged vortices are generated...

Surface plasmon resonance (SPR)-based biosensing is an accurate and sensitive technique used to evaluate the biomolecular interactions in real time in a label-free environment. Several new approaches have been proposed to improve the sensitivity of SPR sensors. The development of sensing surfaces can significantly improve the performance of biosens...

We propose a novel diffractive element to produce a perfect vortex beam. Flexibility in creating any perfect vortex beam is one of the considerable advantages of this method. Moreover, simplicity in creating the element is another interesting feature of this technique. We simply produce the proposed element by shifting the phase of a spiral zone pl...

A novel diffractive element is presented which is made through lateral phase shifted square zone plate bounded along horizontal and vertical axes via two perpendicular rectangle windows, respectively. We demonstrate that \textcolor{red}{under a given condition} the element is able to produce a square light beam at the focal plane. We have also elab...

Extraordinary electrical and optical features of graphene-based materials attract researchers to improve sensing center of different sensors using them. In this research, the effects of sensing molecules on electro-optical features of graphene-based sensors are modeled. The adsorption effect on the Hamiltonian of the system based on tight-binding m...

We aim to present an orthogonal symmetric-based di�ractive lens which has unique focusing properties. The structure of the element is based on the framework of orthogonal zone plate which is constructed by overlaying two perpendicular linear zone plates with opposite topological charges. We illustrate that the proposed element has the sharper focal...

This study examined MQWs made of InGaAs/GaAs, InAlAs/InP, and InGaAs/InP in terms of their band structure and reflectivity. We also demonstrated that the reflectivity of MQWs under normal incident was at maximum, while both using a strong pump and changing incident angle reduced it. Reflectivity of the structure for a weak probe pulse depends on po...

We introduce two models of dark zone - based square photon sieve, in which a desired distribution of light pinholes are inserted into dark zones in the former model, whereas black zones are replaced by black pinholes in the last ones. It is shown that the location and size of the pinholes has an operative effect in increasing diffractive and imagin...

Multi-regioned square zone plate is presented which is achieved by sectioning a square zone plate into several regions. Each region is composed of Fresnel zones in a way that the first zone of a given region is the same as the last zone of the previous ones, from transmission point of view. By numerical studies and experimental works, we show capab...

We introduce and study a novel type of square zone plate, in which square Fresnel zones are azimuthally structured. The effect of the structured parameters on its focusing properties were studied in detail. Simulations show that the main lobe is well modified, as well as the side lobes are reduced in comparison to that of the square zone plate. In...

Exceptional optical and electrical characteristics of graphene based materials attract significant interest of the researchers to develop sensing center of surface plasmon resonance (SPR) based sensors by graphene application. In this research carrier density variant in the form of conductance gradient on graphene based SPR sensor response is model...

We are about to introduce a phase shifted orthogonal zone plate that is a special kind of orthogonal zone plate in which its phase profile is transversely and equally shifted along horizontal and vertical directions. It is demonstrated that the phase shift causes the focal spot to be split into four completely identical spots. It is also illustrate...

Graphene with a single atomic layer of carbon indicates two-dimensional behavior which plays an important role in sensor application, because of its high surface-to-volume ratio. Its interesting optical properties lead to low-cost and accurate optical devices as well. In the presented work trilayer graphene nanoribbon (TGN) with focus on its optica...

Rigorous coupled-wave theory has been implemented to study comprehensively diffraction efficiency of binary metallic gratings. We have investigated diffraction efficiency for TE and TM polarizations and conical incident beam in more detail than the other reported studies. As a general case, we study diffraction efficiency with respect to incident a...

Graphene plays an important role in sensor application, because of its high surface-to-volume ratio. Recently, experimental attention has turned toward trilayer graphene nanoribbon (TGN) because of its tunable band gap and high carrier mobility which are critical for industrial applications so its optical properties such as dielectric constant and...

In order to verify the feasibility of the presented design, we have employed an experimental setup which is schematically shown in Fig. 4. A diffraction pattern is generated at the focal plane and then is recorded by a CCD camera. Recorded results of the aforementioned samples are shown in Fig. 5,6. In Fig. 7 normalized intensity profiles of experi...

An axilens is a combination of an axicon and a Fresnel zone plate to provide a long focal diffractive lens. However, the photon sieve has been known as a high-resolution version of the Fresnel zone plate. Therefore, construction of an axilens on the basis of a photon sieve may yield a high-resolution axilens. To this end, circular zones of an axile...

We introduce a type of Fresnel zone plate (FZP) in which its phase is shifted radially outward. This FZP can easily and precisely turn an incident plane wave into an annular beam at its focal plane. High efficiency and flexibility are the advantages of generating doughnut beams by this method. By performing direct calculations and using Bessel func...

The capability of binary gray scale masks in generating beams with a desired lateral intensity profile is extensively studied in order to fabricate large-angle microprisms. Using a recently introduced technique, some samples based on pulsewidth modulation are designed, so that the pulsewidth is changed with different linear rates from a completely...

The rigorous coupled-wave technique is implemented to analyze a surface-relief dielectric grating in more and unconsidered details. In this work, the effect of various incident angles upon gratings with different ratio of the period to the incident wavelength were widely investigated for both TE and TM polarizations. Impact of number of space harmo...

Fresnel biprism is a one dimensional refractive element that has a lateral linear phase. Having been considered this element as a refractive axicon, its focal depth was evaluated theoretically and experimentally by means of Fresnel-Kirchhoff integral. It is shown that its focal length is a function of its refractive index and its apex angle. Experi...

FFT-based convolution is proposed to numerical solve Fresnel-Kirchhoff integral in Fresnel regime carefully and in a very shorter time in comparison to direct solving convolution. To show its capability, the algorithm was implemented to evaluate amplitude of a diffracted plane wave at the focal plane of photon sieves with different focal lengths. T...

This paper presents a more detailed interaction of an electromagnetics light with a metallic surface-relief subwavelength grating utilizing the rigorous coupled-wave analysis. The focus of this work is the accurate modeling of undetermined aspects of diffraction patterns produced by binary metallic grating structures, specially gold grating. First-...

By impinging a step phase-shifted white light beam on a grating-based interferometer, one of diffraction orders is modulated and interference bands so-called “Talbot bands” are formed. Here, classical Talbot bands set up is generalized to the symmetry configuration, in which two glass plates of the same thickness instead of one plate, are inserted...

Based on precise and detailed theoretical examination of diffusion equation analysis, two-step Ag + − Na + and Na + − Ag + ion-exchange parameters were optimized in order to fabricate a gradient index (GRIN) lens in the BK7 glass rod. Using the diffusion equation, the impact of the concentration ratio of the exchanged ion during the first and secon...

A novel apodized photon sieve is presented in which random dense Gaussian distribution is implemented to modulate the pinhole density in each zone. The random distribution in dense Gaussian distribution causes intrazone discontinuities. Also, the dense Gaussian distribution generates a substantial number of pinholes in order to form a large degree...

A new and simple method for generating binary masks for fabrication of gray scale micro-optical elements is proposed and examined. In this technique the main idea is superimposing two or more gratings with slightly different pitches that depend on the considered gray tone level. This causes generation of a chirped binary mask in which the openings...

Aclass of photon sieve is introduced whose structure is based on the overlapping pinholes in the innermost zones. This kind of distribution is produced by, for example, a particular form of Gaussian function. The focusing property of the proposed model was examined theoretically and experimentally. It is shown that under He-Ne laser and white light...

We demonstrate an easy, reliable, applicable, and sensitive method to measure refractive index of liquids by using Fresnel diffraction. In this method a cylindrical glass rod, in general, or an optical fiber in special case, is immersed into a liquid. Physical parameters of the rod, like radius and refractive index, should be well known. Then, the...

A nondestructive technique, based on Fresnel diffraction from phase objects, is proposed for specifying the refractive indices of optical fibers without requiring index matching liquid. The method involves measurement of normalized intensity distribution on the Fresnel diffraction pattern of a monochromatic plane wave diffracted from a fiber, and e...

A retroreflector array can be used to act as an optical tapped delay-line filter for temporal optical signals. Here, we demonstrate the basic operation and present a theoretical description. Our theory is based on the mathematical formalism for finite impulse response filters. A relationship to the classical Talbot bands experiment is established....

A nondestructive technique for determining the refractive indices of the core and the cladding of step index optical fibers is presented. This method involves diffraction of plane wave from an optical fiber and application the iterative method on Fresnel-Kirchhoff integral, the refractive indices of the core and the clad obtained by this method are...

A nondestructive technique for determining the refractive indices of the core and the cladding of step index optical fibers is presented. This method involves diffraction of plane wave from an optical fiber and application the iterative method on Fresnel-Kirchhoff integral, the refractive indices of the core and the clad obtained by this method are...