Iranian Journal of Physics Research
https://ijpr.iut.ac.ir/
Iranian Journal of Physics Researchendaily1Thu, 22 Aug 2024 00:00:00 +0430Thu, 22 Aug 2024 00:00:00 +0430Experimental Physics, Theoretical Physics: A Comparative Study
https://ijpr.iut.ac.ir/article_3529.html
Investigating the effect of annealing on structural and optical properties of TiO2 and SiO2 broadband reflective layers coated by the plasma sputtering method
https://ijpr.iut.ac.ir/article_3495.html
In this article, the effect of annealing on the structural and optical properties of TiO2 and SiO2 antireflection coatings was investigated. The thin layer was placed on the silicon substrate by sputtering and then annealed for 1 hour at different temperatures. By examining the optical properties of the samples, it was observed that after annealing, the reflection from the surface in the wavelength range of 450-750 nm decreased from 2.7 to 0.23%. The refractive index of the samples also decreased after annealing. Also, by examining the structural properties of the samples, the anatase phase before annealing and the mixture of anatase and rutile and the increase in the intensity of the peaks after annealing were observed.Basic model for calculating the macroscopic temperature of plasma plume and comparison with electron excitation temperature by optical spectroscopy method for non-transferred DC plasma torch
https://ijpr.iut.ac.ir/article_3494.html
Optical emission spectroscopy is known as a prevalent technique for plasma diagnostic which was applied in many experiments. The present research is important and considerable from two points of view. First, with accurate details, the spectroscopy of the plasma plume has been analyzed and it was significant since internationally the plume temperature has been less investigated in comparison with the excited electrons temperature, and also is remarkable as regards the national reports may be even not found such study. In the second view, considering in the non-transfer plasma torch design, the plasma plume temperature estimation and its characterization were substantial and necessary. These results are obtained using the Boltzmann method and exact analysis of the Fortrat curve and the selection of the P branch of the curve known as the first negative system N2+(B-X), based on the dominant Nitrogen molecules in the air. By exact selection of rotational quantum numbers, regarding maximum spectrum intensities, the macroscopic plasma plume temperature, and excited electrons temperature were estimated 2000 (0.17 eV) and 6400 (0.5 eV) Kelvin respectively. The temperature results of this thermal torch sample are compared with international authoritative reports and also with the thermodynamic approach in a similar condition and is in the minimum spectrum of temperature which was excepted. It means that, the macroscopic plume temperature is still far away from related thermal plasma near the excited electron temperature (more than 4000 K). Therefore, to design a desirable plasma torch with suitable electrodes and other parameters, and achieve the 4000 K macroscopic temperature, it is in the minimum spectrum of temperature or efficiency and these obtained results are important and necessary for the precise design of a waste-incinerator torch pursuing with this purpose in the future.Study of the linear and nonlinear optical properties of quantum dot molecules: Tunneling induced transparency
https://ijpr.iut.ac.ir/article_3500.html
In the present work, the linear and nonlinear optical properties of quantum dot molecules composed of two quantum dots as well as three quantum dots molecules, respectively known as double quantum dot (DQD) molecule and triple quantum dot (TQD) molecules are studied using the probability amplitude method, and the obtained results are discussed and compared. By solving the state equations of these systems in the interaction picture, under the rotating wave approximation and the dipole approximation, the first and third-order susceptibilities for DQD and TQD molecules are calculated. A phenomenon called tunneling-induced transparency (TIT) which is similar to electromagnetically induced transparency (EIT) is studied in these types of quantum dot molecules. The effect of key system parameters such as tunneling couplings between quantum dots and the tunneling intensity on the linear and nonlinear optical response of multiple quantum dot molecules DQD and TQD is investigated. It was shown that the position and the width of the TIT window created in these quantum dot molecules can be tuned by changing the physical parameters.Investigating the interplay between helium ash and impurities in an aneutronic fusion plasma environment for sustainable energy production
https://ijpr.iut.ac.ir/article_3501.html
In this research, the effect of helium ash on the ignition and burn condition of aneutronic fusion plasma in the spherical tokamak reactor was investigated. Since the presence of helium ash is unavoidable, we considered the ratio of helium particle confinement time to the energy confinement time &rho;* as a figure of merit. Therefore, the effect of helium concentration by using zero-dimensional coupled equations of power balance and particle balance on the ignition and burn behavior of plasma was investigated. In this research, unlike our previous research, we considered a non-ideal plasma, and the constant concentrations of Be and W impurities were assumed to investigate the effect of common impurities in the environment of spherical tokamak&rsquo;s plasma. In fact, the functions used to calculate the radiation loss power are a new approach based on the latest atomic data and coronal equilibrium model. By numerically solving the equations and attaining the iso-curves, we concluded that the helium concentration in the burn state of the plasma is higher than the ignition state and increasing &rho;* improves the stability in the plasma. The triple product curves close for &rho;*&gt;4.63 in the burn state and for &rho;*&gt;3.0 in ignition state, and there will be no possibility of plasma operational activity.Investigation of electronic and thermal properties of SnN-InO by using density functional theory
https://ijpr.iut.ac.ir/article_3503.html
In this research, electronic and thermoelectric properties of the two-dimensional monolayer of SnN-InO were investigated using density functional theory. The SnN-InO nanostructure is a two-dimensional hexagonal thermoelectric material with an indirect band gap of 0.5 eV. Using the electronic structure, we evaluated the thermoelectric transport coefficients such as the Seebeck coefficient which is the major determinant of thermoelectric properties, electrical conductivity, electronic thermal conductivity, and figure of merit. Calculations illustrate that the Seebeck coefficient declined to some extent with increasing temperature, and had the highest value in the range of Fermi level and negative energies. Another factor to consider is the variations of the figure of merit that are negligible compared to the temperature, so it has undergone changes of about 0.2 in the temperature range of 400K which are reasonable for practical applications. Therefore, the SnN-InO nanostructure can be considered as a qualified thermoelectric material with the figure of merit as 0.9 at room temperature.Simultaneous digital holographic microscopy and Fourier transform spectroscopy
https://ijpr.iut.ac.ir/article_3497.html
Digital holographic Microscopy is a non-destructive and label-free method that provides quantitative phase information in biological and industrial applications. High coherence light sources, such as lasers, are commonly used in digital holographic microscopes. Parasitic -interference fringes and speckle noise in high-coherence sources as well as complex configurations reduce the accuracy of the phase measurements. In this paper, a common-path and low-coherence digital holographic microscopy with a Fourier transform-based spectroscopy is introduced. The low-coherence source used here is an LED and the common path configuration is used based on splitting the wavefront by Fresnel biprism. Reconstruction of the hologram is analyzed using the Fourier method. In addition, The spectral line shape of the LED is obtained simultaneously with the Fourier transform of the visibility of the recorded fringes. The ability to simultaneously perform quantitative phase imaging and Fourier transform spectroscopy makes this system unique in the real-time study of biological samples in micron size.Quantum batteries charging using chain-STIRAP technique
https://ijpr.iut.ac.ir/article_3505.html
In this article, a scheme for charging quantum batteries using the chain-STIRAP technique is proposed. For this purpose, first, a five-level quantum battery is considered and four pulses are used to charge this battery. It has been shown that by properly adjusting the maximum intensity and the time delay between pulses, the conditions of the chain -STIRAP technique can be established and charged the five-level quantum battery properly, so that the maximum amount of ergotropy is achieved. In this scheme, small changes in the parameters of the pulses, including the time delay between the pulses and the maximum value of the pulses, do not have much effect on the final ergotropy of the system. It is also shown that the proposed method in this scheme can be extended to charge quantum batteries with more than five levels.Coherent control of the dynamics of entropy uncertainty of qubits in a dissipative environment
https://ijpr.iut.ac.ir/article_3504.html
In this paper, we study the entropy uncertainty of a composite system consisting of two identical non-interactive subsystems. Each subsystem separately consists of a qubit inside a leaky cavity. It is assumed that the considered qubits independently and simultaneously interact with an external classical field and vacuum electromagnetic modes of their respective cavities. The study suggests that intensity (Rabi frequency) and detuning of the classical field have a significant effect on the dynamics of entropy uncertainty of the total system. So by increasing the intensity of the classical field, entropy uncertainty can be maintained small for a long time. Moreover, it is revealed that the more we increase the detuning, the less time is required to the uncertainty of the system experiences the steady state.A coupled system of \phi^4 and sine-Gordon fields
https://ijpr.iut.ac.ir/article_3520.html
Pairing fields can lead to the emergence of new phenomena. In the classical fields and nonlinear systems, a lot of research has been done on the solitary and soliton solutions of these systems. In the literature, usually, we see the coupling of two&nbsp; ϕ^4 systems, or two sine-Gordon systems. The sine-Gordon system has various solutions, all of which are well-behaved, and its soliton solutions are well known. On the other hand, the&nbsp; ϕ^4 system, which is very important in field theory, has solitary solutions, but no soliton solutions. For example, a bound solution cannot be made from a pair of kink and anti-kink; or these two solutions will not survive after collision, and will be destroyed. In this research, we couple a&nbsp; ϕ^4 system to a sine-Gordon system, in order to extend the stability from the sine-Gordon system to the ϕ^4 system. We have shown that , for a coupled ϕ^4 and sine-Gordon system, this expectation is partially fulfilled.The magnetic and half-metallic properties of the d0-quaternary Heusler alloys KYBX(Y=Ca or Sr, X=S or Se) in ab-initio approach
https://ijpr.iut.ac.ir/article_3498.html
Heusler alloys have attracted much attention due to their unique electronic structure. Most of the research on the Heusler compounds to date, has involved structures that contain transition elements. Recently, quaternary Heusler compounds without the presence of transition metals have attracted attention both from an experimental and a theoretical point of view. We have applied the first-principle method to investigate the structural, electronic, and magnetic properties of the KYBX(Y=Ca or Sr, X=S or Se) quaternary Heusler compounds. The results of our calculations showed that these compounds are ferromagnetic. After examining the different arrangements of atoms in these compounds, it has been determined that the type I of these structures is the most stable configuration. The electronic properties of these alloys indicate that they have a magnetic moment of 2 &mu;B and are magnetic semi-metals with 100% spin polarization at the Fermi level. Their semi-metallic property primarily originates from the p orbitals of B atoms. These compounds are suitable for spintronic applications.Comparison of optical bistability in two different hybrid optomechanical systems: Impact of quantum dot molecules
https://ijpr.iut.ac.ir/article_3499.html
In this paper, optical bistability in hybrid optomechanical systems consisting of two cavities (optomechanical and conventional) coupled to each other, which contain quantum dot molecules (QDMs), is investigated and compared. For this purpose, two different configurations are studied: in the first configuration, the quantum dot molecules (QDMs) are inside the optomechanical cavity, and in the second configuration, the quantum dot molecules are inside the conventional cavity. To calculate the dynamics of the system operators, the Heisenberg-Langevin approach is used under the mean field approximation. To achieve the phenomenon of optical bistability, which is used in optical switches and optical memories, the dynamic equations of the system are solved in a steady state. The effect of the system's physical parameters, including the detuning, the number of quantum dot molecules, and the tunneling intensity of the external field, on the phenomenon of optical bistability is studied. In addition, the switching threshold and the width of the optical bistability region in two different configurations are compared. Considering that the phenomenon of optical bistability can have potential applications in all-optical switches, optical transistors, quantum computing, and quantum communication, the obtained results can be useful for the mentioned applications and system optimization.Dynamics of Quantum Coherence and Hilbert-Schmidt Speed of V-Type Three-level Atom in Anisotropic Photonic Crystal
https://ijpr.iut.ac.ir/article_3525.html
In this paper, the time evolution of quantum coherence and Hilbert-Schmidt speed, as a criterion to measure the memory of the quantum system, of a V-type three-level atom embedded in an anisotropic photonic crystal are investigated. The effect of the different relative positions of the upper levels from the forbidden gap and the initial relative phase values on the mentioned quantum features are studied. We show that the photonic band gap crystal, as a structured environment, significantly influences the preservation and enhancement of these quantum features. The photonic gap band materials have non-Markovian properties and offer a new approach as a basic solution in overcoming the decoherence problem and subsequently in problems related to quantum information.Investigation of the performance of T-carbon ِnanostructure as optical absorbing material under hydrostatic stress
https://ijpr.iut.ac.ir/article_3496.html
In this research, we use first-principles calculations based on density functional theory (DFT) to investigate the electro-optical performance of a three-dimensional T-carbon nanostructure. In addition to analyzing the dynamic and static stability of the optimized structure of the T-carbon unit cell, as new research, the electro-optical properties of T-carbon, under the effect of omnidirectional hydrostatic stress on the unit cell up to 9 GPa, were simulated by using computational codes. The obtained results indicate the acceptable performance of this nanostructure as a suitable optical absorbent material. This three-dimensional nanostructure can be used to design innovative components such as electro-optical sensors, light intensifiers, optical detectors, and organic perovskite solar cells.The effect of geometrical parameters on the thermoplasmonics properties of gold nanostars for photothermal therapy
https://ijpr.iut.ac.ir/article_3502.html
In recent years, there has been an increasing interest in using plasmonic nanoparticles as heat sources with the ability to be controlled remotely by light, which has led to the emergence of the field of thermoplasmonics. In this regard, gold nanostars are unique nanomaterials with the inherent ability to create a limited thermal effect at the nanoscale. Therefore, in this article, the plasmonic and thermoplasmonic properties of gold nanostars have been investigated. In addition, the changes caused by some geometrical parameters such as the size of nanoparticles and their thickness on the local electric field enhancement and increasing the surface temperature of nanostars have been reported.using of deep learning on designing and optimizing an optical fiber temperature sensor with isopropanol cover
https://ijpr.iut.ac.ir/article_3524.html
In this paper, an optical fiber temperature sensor is designed that uses isopropanol to increase temperature sensitivity and deep learning to characterize changes in the three-dimensional pattern of light propagation along the optical fiber and determine the ambient temperature. In other words, changing the ambient temperature changes the refractive index of isopropanol and causes a change in the appearance of the interference pattern of the guided modes inside the optical fiber, which identifies the pattern based on deep learning detects the changes in the appearance of light emission and estimates the ambient temperature optimally. In this regard, the mentioned optical fiber was simulated by Rsoft software for 106 different temperatures and their 3D propagation patterns were obtained. From the collection of simulated patterns, a complete database of propagated light for the temperature range of -73 to 82 degrees Celsius has been formed. The mentioned database is entered into the pattern recognition algorithm based on deep learning, and the pattern recognition system is taught how the appearance of light propagation changes in the fiber with temperature changes. The model used in this article is inspired by the AlexNet network and can obtain the ambient temperature with a minimum mean square error of 2.