Department of Atomic Molecular Physics (2015 - Present)
Energy engineering and physics, Amirkabir University of technology, Tehran, Iran
Research field: LED, Solar Cell, Laser
Expert:
Phone: 82884488
Address: Room: 4206, Physics Division, Basic Sciences Department
Elnaz Yazdani has completed her BSc in Physics at Tabriz University and earned her PhD in laser plasma interaction from Amirkabir University of technology in 2014. In her PhD dissertation, she has focused on proton acceleration in intense-ultra-short laser pulse interaction with solid target, experimentally and theoretically. She is now conducting a research group in laser-optics at Tarbiat Modares University, focusing more on developing hybrid organic-inorganic material for next generation optoelectronic devices and particle acceleration in laser plasma interaction.
Responses of the uniform near-critical plasma (UNCP) and nano-porous near-critical plasma (NPNCP) upon interaction with a short-intense laser have been scrutinized using two-dimensional (2D) particle-in-cell simulations. Maximum proton energy variation by the deposition of uniform and nano-porous layers in front of a solid target for a wide range of laser intensities (normalized amplitude a0 = 5–25) and average densities of the front layer ne = 0.3 − 3nc (where nc is the critical density) has been parametrically studied. It is found that the proton maximum energy for the front layers with sub-10 ?m thicknesses is independent of the target porosity and density. However, in the relatively thick targets, the nano-porous structure decreases
One of the most common laser proton acceleration mechanism is Target Normal Sheath Acceleration (TNSA) method. The use of a foam layer in front of the main target plays an important role in the amount of laser energy absorption by the electrons and consequently the acceleration of the proton. The front layer can be either uniform and homogeneous or nano-structured. In this study, by assuming a nanostructured foam layer, and using two-dimensional particle simulations code, the effect of nanoparticle’s radius on the proton cut-off energy is investigated. Particles with radii of 10, 60 and 120 nm and random sizes in the range of 10 to 120 nm have been studied and simulated in a front layer with thickness of 10 and 20 μ m with near-critical
This study represents the investigation of earth-abundant and non-toxic CZTSSe absorber materials in kesterite solar cell by using the Finite Element Method (FEM) with (1) electrical, and (2) optical approaches. The simulated results have been validated with the experimental results to define guidelines for boosting the cell performance. For improving the cell efficiency, potential barrier variations in the front contact, and the effect of different lattice defects in the CZTSSe absorber layer have been examined. Controlling the defects and the secondary phases of absorber layer have significant influence on the cell performance improvement. Previous studies have demonstrated that, synthesis of CZTSSe: Na nanocrystals and controlling the S/
Nanostructured materials have attracted much attention in recent decades. Nowadays, there are numerous nanomaterials with several applications. The ultrasonic spray pyrolysis method is a cost-effective and adaptable technique based on an aerosol process for synthesizing nanoparticles and depositing thin films. The technique is capable of synthesizing metal, oxide, and composite nanomaterials with precisely controllable morphologies and chemical compositions using metal salts in aqueous solvents. More importantly, it is popular, as evident from the growing number of studies being conducted on the technique. Here, we review studies conducted on basic principles and applications of the ultrasonic spray pyrolysis method and investigate effects
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Proton acceleration process by the generated sheath in the rear-side of an Al target in the interaction of P polarized laser with the pulses duration of≥ 40 fs and intensity of 3. 6? 1019 W cm-2 has been experimentally and numerically studied. The results show that by employing the positively chirped pulse, the proton cut off energy and the number of the accelerated protons are increaesd in comparison with an unchirped and negatively chirped pulse interactions. After that, the electron heating process in interaction of positivly and negativly chirped pulse is investigated and correlation between the chirped parameter and produced electrostatic field in the backside of the target is studied. Particle-in-cell simulation results show that th
Nonlinear evolutions of an ultra-intense, short laser pulse due to the wake excitation inside the plasma are studied by means of detailed Particle-In-Cell (PIC) simulations and comprehensive analyses. Pulse lengths both longer and shorter than the plasma wavelength are considered. It is turned out that the system shows adiabatic behavior as long as the plasma evolves very slowly in the Pulse Co-Moving (PCM) frame due to the ignorable radiation back-reactions. A sophisticated treatment of the adiabatic regime is presented, based on the proper application of the local conservation laws in the PCM frame in conjunction with the Lorentz transformations. In this context, equations for the overall pulse evolutions are reduced into a single equatio
The transition from hole-boring to light-sail regime of radiation pressure acceleration by frequency-chirped laser pulses is studied using particle-in-cell simulation. The penetration depth of laser into the plasma with ramped density profile increases when a negatively chirped laser pulse is applied. Because of this induced transparency, the laser reflection layer moves deeper into the target and the hole-boring stage would smoothly transit into the light-sail stage. An optimum chirp parameter which satisfies the laser transparency condition, , is obtained for each ramp scale length. Moreover, the efficiency of conversion of laser energy into the kinetic energy of particles is maximized at the obtained optimum condition. A relatively narro
A comprehensive theory is proposed to describe the propagation and absorption of ultra-intense, short laser pulse through the under-dense plasma. The kinetic aspects of plasma are fully incorporated using extensive particle-in-cell (PIC) simulations. It is turned out that the plasma behavior is characterized by both its density and the ratio of the pulse length to the plasma wavelength. According to exact analyses and direct simulation evidences, at ultra-low densities the laser pulse is adiabatically depleted (absorbed) by the wake excitation. And the depletion is accompanied by the overall radiation red-shift. At these densities, for pulse lengths larger than the plasma wavelength the Raman type scatterings also occur without causing inst
Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum plasma with considering a ramped density profile. In this density profile due to the increase in the plasma density, an earlier and stronger self-focusing effect is noticed where the beam width oscillates with higher frequency and less amplitude. Moreover, the effect of the density profile slope and the initial plasma density on the laser propagation has been studied. It is found that, by increasing the initial density and the ramp slope, the laser beam focuses faster with less oscillation amplitude, smaller laser spot size and more oscillations. Furthermore, a comparison is made among the laser self-focusing in thermal quantum plasma, cold quantum
The electron residual energy originated from the stochastic heating in under-dense field-ionized plasma is investigated here. Initially, the optical response of plasma is modeled by using two counter-propagating electromagnetic waves. In this case, the solution of motion equation of a single electron indicates that by including the ionization, the electron with higher residual energy compared with that without ionization could be obtained. In agreement with chaotic nature of the motion, it is found that the electron residual energy will be significantly changed by applying a minor change in the initial conditions. Extensive kinetic 1D-3V particle-in-cell simulations have been performed in order to resolve full plasma reactions. In this way,
Propagation of Gaussian X-ray laser beam is presented in collisional quantum plasma and the beam width oscillation is studied along the propagation direction. It is noticed that due to energy absorption in collisional plasma, the laser energy drops to an amount less than the critical value of the self-focusing effect and consequently, the laser beam defocuses. It is found that the oscillation amplitude of the laser spot size enhances while passing through collisional plasma. For the greater values of collision frequency, the beam width oscillates with higher amplitude and defocuses in a shallower plasma depth. Also, it is realized that in a dense plasma environment, the laser self-focusing occurs earlier with the higher oscillation amplitud
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