نشریه اپتوالکترونیک
سال چهارم شماره 1 (پیاپی 10، پاییز و زمستان 1400)

In this article, the effect of creating a central symmetric defect on the Faraday rotation and transmission in a one-dimensional magneto-optic photonic crystal consisting of two dielectric materials and one magneto-optic material has been studied. After creating the defect, the effect of increasing the volume of the defect on the width of band gap and the number of transmitted modes with Faraday rotation in the band gap area has been investigated. The highest rotation achieved in this structure is -27˚ and the highest transmission is 0.917.

In this experimental work, we have studied light polarization effects on the nonlinear refractive of dyed liquid crystal. Therefore, homogenously aligned Solvent Green 3 dye doped 5CB liquid crystal cells with 50 micrometer thickness were used and their nonlinearity were investigated using linear polarized He-Ne laser at 632 nm with polarization 0-90 degree with the director of cells. It was observed that in the parallel and orthogonal polarization of light relative of director the nonlinear refractive of samples is negative and positive respectively.

Plasmonic cloaking is one of the invisibility methods which is very attractive for researchers. Despite of non-perfect nature of this method, there are some advantages such as easier practical realization for it. In this paper, considering cylindrical layered metamaterial with composition of graphene and TiO2 layers, wave equation is solved for this structure analytically. After calculating scattering cross section, invisibility condition is investigated in the structure. Then, the effect of changing in some geometrical and physical parameters such as chemical potential, core radius and number of layers on invisibility condition is analyzed. Some numerical simulation using COMSOL approve the results.

The interaction of intense femtosecond laser pulses with argon nanoclusters is investigated in the framework of the nanoplasma model. According to the nanoplasma model, ionization, heating and, expansion of the cluster occurs during and after the laser-cluster interaction. The production of energetic electrons is one of the results of this type of interaction. As the intensity of the femtosecond laser increases, the energy, density of the electrons, and hydrodynamic pressure, increase. It is shown that using the double-pulse lasers in interaction, the mentioned quantities are significantly modified compared to the interaction with the single-pulse lasers. The use of double-pulse lasers instead of single-pulse lasers in interaction with atomic clusters at equal intensities improves ionization and increases the energy of electrons, and also the hydrodynamic pressure is improved by 39%. The influence of delay time between two pulses also is investigated. It is found that by choosing the suitable delay time higher energy electrons can be obtained.

One of the non-invasive methods of cancer treatment is photothermal laser therapy. Adding metal nanospheres and nanorods to tissue improves the healing process. On the other hand, temperature control is also essential to maintain healthy tissue. This article investigates the process of cancer treatment using laser and cobalt oxide nanoparticles as well as iron and copper metals. For this, we consider cobalt oxide nanospheres in a spherical cancer cell; Then, a number of cylindrical cobalt oxide nanorods are regarded in an aqueous hemisphere (as a cancer cell) and simulated with the help of COMSOL finite element approximation software. Appropriate boundary conditions are important for heat transfer on internal and external surfaces and temperature distribution should be obtained in different parts of the cell and nanoparticles. In addition, we investigated the magnetic and non-magnetic effects of iron and copper metals with the same laser intensity and similar boundary conditions. The calculation results show that the average temperature of the cell water volume during the first 0.8 microseconds of irradiation in the presence of cobalt oxide nanospheres is 43 degrees Celsius; also, in the presence of cobalt oxide nanorods, it reaches a temperature of 53 degrees Celsius. The average temperature of the water volume of the cell reaches 100 degrees Celsius in the presence of iron nanospheres and 100 degrees Celsius in the presence of copper nanorods with a steeper slope.

In this study, we investigate the properties of spin-dependent electrical transport in molecular nano structures through a heterogeneous molecular bridge of fullerene and the pentacene molecule as an electron acceptor and donor, coupled to two semiconductor copper electrodes. For this purpose, we determine the spin-dependent Hamilton for a single band and, using the Green function approach in the context of strong dependence, the dependence of the electrical conductivity properties of the spin-circuit interaction, as well as the applied voltage on this structure. . The results of the calculations show that the spin polarization is up to 80% effective in controlling the spin of the descending electrons. This heterogeneous molecular nano structure may be useful in the design of spintronic devices.

Nitrogen-vacancy center, consisting of a nearest-neighbor pair of a nitrogen atom, which substitutes for a carbon atom, and a lattice vacancy, is a point defect in diamond. This system is one of the most important candidates for implementing quantum information processing. In this paper, the application of such a system in the process of quantum estimation is investigated. In particular, the estimation of the initial phase, which can encode significant information, is examined precisely. In addition, we study the effect of the entanglement between the system and its environment as well as the fidelity of the evolved state to the initial one, on the accuracy of the phase estimation.

The transport properties of cargo carriers for organic semiconductors depend on the presence and distribution of trap sites. As we know, traps are the result of irregularities in polymer molecules and chains caused by physical or chemical impurities in the structure of organic semiconductors. From the point of view of crystal defects that cause changes in energy levels and create energy gaps in band theory, the transport properties of cargo carriers in this type of systems will also undergo changes, the most important parameter of which is being replaced or trapped. Will be in the delivery process. Of course, defects can play a role in the distribution centers in the system.In this paper, using different combinatorial models of carriers, the effects of basic parameters on the performance of heterogeneous organic solar cells as well as charge transfer are investigated. In order to simulate these processes, in this section, the basic parameters of P3HT: PCBM-structured organic solar cells have been studied by using the self-consistent solution of momentum-diffusion equations and Poisson equation, as well as using different recombination models by finite element method.

So far, most of researches and investigations have been based on absorption and surface plasmon waves propagation on graphene and its various realized patterns mounted over isotropic substrates. In this paper, at first the structure of graphene over hexagonal boron nitride, as an anisotropic substrate, its effective permittivity and reflection coefficient, and also, the possibility of their tuning through change in graphene Fermi level, is studied. Then, characteristics of surface plasmon waves propagation on graphene nano-ribbons mounted over uniaxial anisotropic substrate are investigated analytically and numerically. Employing such substrates can decrease propagation loss in comparison with other substrates dramatically. The results of this investigation can be utilized in analysis of absorbers and periodic arrays of graphene nano-ribbon over hexagonal boron nitride substrates.

first principles calculation, we investigate electronic and optical properties of graphene with B, N, O and F adsorption. For the adatom studied the distortion of the graphene layer is quite significant and cause to change hybridization from sp2 to sp3 also we found that B, F and O adsorptions are n-type, p-type and direct semiconductor respectively while N adsorption has a metal behavior. N absorbed graphene show magnetic moment, while B, O and F absorbed graphene exhibit no magnetic moment. The absorption spectrum of monolayer graphene have been calculated for the cases of in plane (E⊥c), out of plane (E‖c) polarization of light and 45° to the plane of graphene layer and compared with atom adsorption on graphene and it was observed that For the case of (E⊥c) the graphene is an optical sensor for finding F atom and in the case of (E‖c) it is an optical sensor to find B atom in environment.

In this study, we investigate the effect of magnetic field on energy states at the GaAs/〖Ga〗_(1-x) 〖Al〗_x As/GaAs quantum dot and the 〖Ga〗_(1-x) 〖Al〗_x As/GaAs/〖Ga〗_(1-x) 〖Al〗_x As quantum anti-dot. Based on the finite difference method numerical calculations show that the magnetic field effect on the energy states of quantum dots and quantum anti-dots is quite different. Also, using three types of linear polarization (LP), right circular polarization (RCP) and left circular polarization (LCP), the Oscillator strength for 1s→2p for the quantum dot and quantum anti-dot point at the presence of the magnetic field is calculated.

The magnetic and electronic properties of Pd2S4 monolayer were done through doping nonmetals NM(N,P,As,O,Se,F,Cl,Br) and by using first principal calculations. The results show that nonmetals with an odd number of valence layers motivate magnetization of the structure, while non-metals with an even number in the valence layer do not induce magnetic property in the system. The highest amount of magnetization generated is due to the doping of seventh group atoms and especially the Br atom with a value of 0.81 µB. In the fifth group, from top to bottom (increasing the period), the value of spin-orbital p separation decreases, which corresponds to a decrease in the value of magnetization. While the value of spin-orbital separation P of the atoms of the seventh group increases with the increase of the period, so the value of magnetization of the atom The seventh group increases from the top to the bottom of the periodic table. In the seventh group, in contrast to the fifth group, the magnetization of the first neighboring sulfur atom is higher than that of the doping non-metal atoms. The findings obtained in this work can initiate experimental exploration and expand the application of non-metal doping in spintronic devices.