Mohammad Yeganeh
@iasbs.ac.ir
Physics
IASBS
Mohammad Yeganeh currently works at the Department of Physics, Institute for Advanced Studies in Basic Sciences. Mohammad does research in Optical Physics, Fluid Dynamics, Atmospheric Physics and Singular Optics. Their current project is "Development of the use of moiré technique in singular optics".
EDUCATION
• B.Sc.: University of Tabriz, Tabriz, Iran, 1999-2003, Physics.
• M.Sc.: University of Tabriz, Tabriz, Iran, 2003-2006, Atomic & Molecular Physics (Laser).
• PhD.: Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran, 2010- 2016, Physics (Optics).
• Postdoctoral Research Associate: Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran, 2017- 2018.
RESEARCH INTERESTS
Moiré TechniqueAtmospheric Turbulencevortex beamsInterferometrywave-front sensorsLiquid CrystalsLaserNonlinear OpticsPhotonicsExperimental PhysicsOpticsOptics and PhotonicsOptical PhysicsLatexPhase SingularitiesMATLABQuantum Optics and Quantum InformationDiffractionPhysical OpticsBirefringenceFo
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
P. Soleimani, H. Khoshsima, and M. Yeganeh
Springer Science and Business Media LLC
AbstractIn this paper, we investigate the generation and controlling of the optical vortex beam using a dye-doped liquid crystal (DDLC) cell. The spatial distribution of the quasi-sinusoidal orientation of the liquid crystal molecules creates a quasi-sinusoidal phase grating (PG) in the DDLC cell. Depending on the incident light pattern, Trans to Cis photoisomerization of the dye molecules affects the orientation of the liquid crystal molecules. To do so, an amplitude fork grating (FG) is used as a mask, and its pattern is stored in the cell by a pattern printing method as the PG. One of the particular features of the stored grating in the cell is its capability in the diffraction efficiency controlled by the applied electric field. The results show, based on the central defect in the FG pattern, the diffracted probe beam in different orders is optical vortices. As a new technique, this type of stored pattern acts like an amplitude grating but according to the results, its structure is in fact a PG. This technique leads to the vortex beam switching capability by applying an electric field to the cell. The results show that by applying 22 V, all the diffraction orders vanish. Meanwhile, the vortex beams reappear by removing the applied voltage. The diffraction efficiency of the vortex beams as well as its generation dependency on the polarization of the incident beam studied. The maximum efficiency of the first diffraction order for linear polarized incident beam was obtained at 0 V, about 8%. Based on the presented theory, a simulation has been done which shows the Cis form of the dye molecules has been able to change the angle of LC molecules on average about 12.7°. The study of diffracted beam profiles proves that they are electrically controllable vortex beams.
Daryoush Abdollahpour, Morteza Lotfollahi, Mohammad Yeganeh, and Saifollah Rasouli
IOP Publishing
The generation of pure third-order spatial phase is the top requirement for the generation of Airy beams through the Fourier-space beam shaping method. Utilizing coma aberration for inducing such a phase profile is shown to be one of the most appropriate approaches because of providing continuous phase, the capability of working at high laser powers, and low costs. Here, we demonstrate pure tunable third-order spatial generation through aberration control in a positive one-dimensional tilted cylindrical telescopic system, and experimentally verify its quality and tunability by two independent wavefront sensing methods namely moiré deflectometry and four-step phase-shifting interferometry. The deflectometry method is used for a real-time visual assessment of the quality of the imprinted wavefront, and also for a quantitative analysis of the wavefront and its dependency on the parameters of the system, while, the interferometric method is used for more rigorous measurement of the generated wavefront. It is shown that by changing the tilt angle of the system, the modulation depth of the cubic phase can be tuned. It is also shown that nearly-complete third-order form of the imprinted phase over a large aperture results in high-quality Airy beam generation with a small truncation factor.
Mohammad Yeganeh and Saifollah Rasouli
The Optical Society
This work presents a very simple and comprehensive approach for classification of the combinational spatial frequencies of the superimposed periodic or quasi-periodic structures. The reciprocal vectors of the structures are used to express their respective spectral components, and a unique reciprocal vectors equation is introduced for presenting the corresponding combinational frequencies. By the aid of the reciprocal vectors equation we classify moiré patterns of combinational frequencies into four classes: the conventional moiré pattern, moiré fringes of higher-order harmonics, higher-order moiré patterns, and pseudo-moiré patterns. The difference between the moiré fringes of higher-order harmonics and higher-order moiré patterns is expressed in the formulas. By some typical examples, conditions for simultaneous formation of moiré patterns of different harmonics of the superimposed gratings are investigated. We show that in the superimposition of two gratings, where at least one has a varying period and another has a non-sinusoidal profile, different moiré patterns are formed over different parts of the superimposed area, where a distinct pair of spatial frequencies of the superimposed structures contributes to the formation of each of the patterns. We use the same procedure in the analysis of simultaneously produced defected moiré patterns in the superimposition of a linear grating and a zone plate, where one or both consist of some topological defects at specific locations and at least one of the gratings has a non-sinusoidal profile. The topological defects of resulting moiré fringes are similar to those appearing in the interference patterns of optical vortices. It is shown that the defect number of resulting moiré fringes depends on the defect numbers and order of frequency harmonics of the gratings. The dependency of the defect number of the moiré fringes and its sign to the defect numbers of the gratings and their contributed frequency harmonics is derived for both additive and subtractive terms of moiré fringes, and the results are verified with several examples based on computational simulations.
Saifollah Rasouli, Fereshteh Sakha, and Mohammad Yeganeh
IOP Publishing
In this paper, we introduce the use of an infinite-mode double-grating interferometer in investigating the fluid dynamics induced by a thermal lens when an intense laser beam—which we call the pump beam—passes through a liquid sample containing strongly absorbing nanoparticles. As the pump beam passes through the sample in normal conditions, since absorption occurs over the beam’s trace, temperature increases and density decreases. The density and temperature changes in the sample can be translated to a phase shift in the passing of a plane probe beam through the sample. By causing two parts of the probe beam to interfere, one part passing from the thermal lens area and the other from another area of the sample spatially separate from the first, it is possible to determine the phase shift value. When the propagation directions of the interfering beams are parallel, infinite-mode double-grating interference fringes are formed. In the infinite mode, the formation and evolution of interference fringes directly reflects any change of density or temperature in the sample. The thermal convection is detected visually and quantitatively determined by chasing the first infinite-mode interference fringe produced. In this work, the measurement of the thermal convection velocity is reported in detail. The measured value is comparable with values obtained with other methods under the same conditions. The proposed method is reliable and very simple; further, the convection process can be visualized in real-time.
Davud Hebri, Saifollah Rasouli, and Mohammad Yeganeh
The Optical Society
For convenient optical communications by the aid of vortex beams, topological charge (TC) alterations should be translated to the change in intensity of the output light. In this paper, we formulate and experimentally investigate diffraction of vortex beams from amplitude radial gratings having sinusoidal profiles. We show that the diffraction pattern simply renders both TC and twist direction of the impinging vortex beam. When the TC of the vortex beam and the radial grating spoke number are equal, intensity on the optical axis of the Fraunhofer pattern gets a maximum value. Otherwise, its value on the optical axis remains zero. We examined the method on different vortex beams; the measured TCs of generated beams are in excellent agreement with the expected values. We show that an alteration between two vortex beams, in which one has a TC equal to the grating spoke number, is translated to a binary change in intensity of the output light on the optical axis. This feature might find wide applications in optical communications.
Saifollah Rasouli and Mohammad Yeganeh
The Optical Society
In this work, by using a local reciprocal vector concept, we introduce a considerable number of quasi-periodic structures where each of them is constructed by a set of curved lines with varying period. By using a simple and very comprehensive recently proposed method, formulations and characterizations of the various moiré patterns of different pairs of curved line quasi-periodic structures are presented. Some advantages of the concept of local reciprocal vector in the area of curved line quasi-periodic structures are clarified.
Mohammad Yeganeh and Saifollah Rasouli
The Optical Society
In this work, for the first time to the best of our knowledge, an investigation on the moiré patterns of superimpositions of two radial or two circular gratings consisting of topological defects and their mutual superimpositions with each other, or with linear forked gratings or defected zone plates, is presented. For characterization of the resulting moiré patterns, we use the reciprocal vectors approach. In this approach, by considering local spatial frequencies for the superimposed structures, their reciprocal vectors are determined from the transmission function of the structures. The local reciprocal vector of the resulting moiré pattern at a given point is determined in terms of the local reciprocal vectors of the superimposed structures defined at the same point. In this approach, the topological singularities of the superimposed structures are described by the azimuthal component of the reciprocal vectors. This formulation is very simple, uniform, and comprehensive. In this work, we offer a detailed discussion on the different resulting moiré patterns for the above-mentioned superimpositions and some potential applications of the proposed superimpositions are introduced. In addition, different resulting moiré patterns are simulated.
Saifollah Rasouli and Mohammad Yeganeh
IOP Publishing
The use of moiré pattern of superimposition of linear forked gratings (LFGs) and Fresnel zone plates (ZPs) has already been reported for study of different physical effects. In spite of a considerable number of applications, there is no comprehensive formulation for this kind of moiré pattern. In this work, we introduce a new family of ZPs containing topological defects that we named defected ZP (DZP) and we present a very simple, uniform, and comprehensive formulation for the moiré pattern of superimposition of two LFGs, two DZPs, and superimposition of an LFG on a DZP, using the reciprocal vector approach. For the case of the two LFGs superimposition, we show that the resulting moiré pattern has a starlike shape or is a large-scale LFG pattern. In the case in which two DZPs are superimposed, we show that the resulting moiré pattern has three general forms: large-scale DZP pattern, starlike pattern, and large-scale LFG pattern. In the superimposition of an LFG on a DZP, in special conditions a new spiral ZP having a topological defect is produced in which its defect number related to the superimposed gratings structures. The presented formulation has potential applications in singular optics measurements.
Mohammad Yeganeh, Saifollah Rasouli, Mohsen Dashti, Sergei Slussarenko, Enrico Santamato, and Ebrahim Karimi
The Optical Society
An approach based on the two-channel moiré deflectometry has been used to measure both wavefront and transverse component of the Poynting vector of an optical vortex beam. Generated vortex beam by the q-plate, an inhomogeneous liquid crystal cell, has been analyzed with such technique. The measured topological charge of generated beams are in an excellent agreement with theoretical prediction.
A. Jafari, A. Ghanadzadeh, H. Tajalli, M. Yeganeh, and M. Moghadam
Elsevier BV
A. Jafari, A. Ghanadzadeh, H. Tajalli, and M. Yeganeh
Elsevier BV