Showing 11 results for Lotfi
Alemeh Asadpour, Rahim Lotfi, Hasan Khandan,
year 20, Issue 0 (1-2014)
Abstract
In this paper Pb1-xSnXS nano Structur particle were synthesized by chemical precipitation method at room temperature under N2 atmosphere. Optical absorption and optical emission were studied by UV- visible spectrophotometer and photoluminescence spectroflurimeter respectively. Structural properties of samples were investigated by X- ray diffraction (XRD). XRD spectra shows that nanoparticles with cubic structure are formed, which increases with increasing of Sn concentration. The optical absorption spectra of the samples indicates that ban gap energy of the samples increases with increasing Sn concentration. PL spectra shows that all Sn doped samples have two emission peaks in visible region.
Malihe Maghouli, Dr Rahim Lotfiorimi, Dr Masood Bazi Javan,
year 21, Issue 0 (3-2015)
Abstract
Abstract-In this paper, the CdS and CdS/SnO2 thin films are prepared by using spray pyrolysis technique.The structural and optical properties of prepared samples characterized by x-ray diffraction(XRD), UV-Vis spectroscopy. Structural analysis of the samples by x-ray diffraction spectra show hexagonal phase for CdS. Optical analysis of the samples by UV-Vis spectrometer show that band gap of CdS/SnO2/glass ratio of the layer of CdS / glass rose.
Reza Kheradmand, Fariba Lotfi,
year 21, Issue 0 (3-2015)
Abstract
Relaxation oscillation frequency and damping rate are the important characteristics of vertical cavity surface emitting laser (VCSEL). These two parameters are important in the current modulation because of the laser output power depend on them. In this paper, the effect of current modulation on the relaxation oscillation frequency and characteristics of cavity Solitons have been studied. The influence of current modulation bandwidth in semiconductor lasers is studied at Soliton regime. Because of having higher optical gain in cavity Solitons comparing with ordinary points in transverse plane of semiconductor laser, better results are expected from current modulation response of cavity Solitons.
Abdolrahman Namdar, Jafar Lotfi, Babak Abdollaipour,
year 21, Issue 0 (3-2015)
Abstract
Abstract- In this paper, we investigate the properties of photonic band gap in one-dimensional graphen photonic crystal with transfer matrix method. We consider the structure in which, single-layer grapheme layers separated alternatively by air laye. The dependence of photonic band gap on polarization and air layer thickness for different frequencies and incident angles are considered. These results can be used to design optic devices based on graphen photonic crystals.
Ms Hanieh Rezaei, Ms Sareh Arjmand, Ms Aram Barzegar, Mr Abbas Sahebghadam Lotfi, Mr Rasool Malekfar, Ms Hori Ghaneialvar, Mr Naser Jafarzadeh, Ms Aleme Mohamadpoor,
year 21, Issue 0 (3-2015)
Abstract
In the present study, spontaneous Raman scattering of two cells was examined. The first cell sample belongs to adipose derived mesenchymal stem cell as an adult stem cell with high potential in clinical studies and cell therapy. The second sample was HepG2 cell line. The cells were cultured on quartz disc to decrease the effects of fluorescence during spectroscopy. 15 different spectra were recorded for each sample and the differences were investigated after spectra average processing. The results revealed that Raman scattering spectra have considerable differences for two cell samples and the technique can be used as a powerful method for the cell fingerprinting purposes.
Ms. Hoda Alsadat Lotfipour, Ms. Sareh Shahidani, Dr. Rasoul Roknizadeh,
year 22, Issue 0 (2-2016)
Abstract
In this article the optomechanical system is driven with the narrow-band squeezed vacuum probe field and the mean square fluctuation in momentum of movable mirror is investigated. It is shown that the state of the mirror will be squeezed. In the cooling situation the squeezing is maximum. In this condition, one gets transferring of the squeezing from input probe to the fluctuations. Finally, the effect of squeezed light parameters on the squeezing of the Nano-mechanical oscillator has been studied.
Ahmad Lotfiani, S. Majid Mohseni Armaki, Majid Ghanaatshoar,
year 26, Issue 0 (ICOP & ICPET 2020 2020)
Abstract
We propose a miniaturized surface plasmon biosensor with electrical response with no need to the external optical spectrometer. The proposed sensor consists of a TCO-I-M junction, deposited on a prism and coupled to a planar waveguide. We show that the output open circuit voltage can be utilized to inspect the surface plamon resonance and the analyte refractive index. We use transfer matrix method and electron transport equation in the metal to obtain the optical and electrical response of the proposed structure. The electrical sensitivity of our introduced sensor is estimated to be
V/RIU.
Fariba Lotfi, Nafiseh Sang-Nourpour, Reza Kheradmand,
year 27, Issue 2 (ICOP & ICPET 2021 2021)
Abstract
We design a novel, real-time and accurate plasmonic sensor made of Mach-Zehnder Interferometer. Our plasmonic sensor structure composed of slab waveguides with lossy dispersive media with negative permittivity and positive permeability such as metal and graphene in the cladding of waveguide and the core of waveguides is dielectric media. In the proposed sensor structure, the sample is located near the upper branch of the interferometer. When the graphene is used at the interface between the core-cladding of the waveguide, the sensor is tuned by applying a gate voltage, with a sensitivity of 180 THz / RIU is achieved.
Ahmad Lotfiani, S Majid Mohseni Armaki, Majid Ghanaatshoar,
year 27, Issue 2 (ICOP & ICPET 2021 2021)
Abstract
In this study, we propose a compact high-sensitivity surface plasmon biosensor with an electrical response based on Fano resonance in M-I-TCO junction integrated with the planar waveguide. The SPR excitation of the M-I-TCO junction enhances the photoabsorption and hot electrons generation, which can produce photocurrent. We demonstrate that the coupling between the MIM junction surface plasmon and wavegude modes can result in modulation of output photocurrent by variation of analyte refractive index. The response of this sensor was calculated in detail and the results showed that the Fano-like profile appears in the photocurrent curve as well as the reflectivity curve which have enhanced sensitivity of biosensors to 66 mA/RIU
Zahra Bagheri, Hoda Sadat Hodalotfipoor, Majid Khodabandeh,
year 28, Issue 2 (ICOP & ICPET 2022 2022)
Abstract
The interference of a single photon which is one of the most mysterious concepts of quantum mechanics is studied. Using a nonlinear crystal, a pair of photons by spontaneous parametric down-conversion are produced. One of them passing through a Mach- Zander interferometer due to the principle of indistinguishability of the paths, interferes with itself. An interference pattern is obtained by recording the coincidence between the correlated photons.
hoda Sadat Lotfipour, Majid Khodabandeh, Zahra Bagheri, Hassan Sobhani,
year 28, Issue 2 (ICOP & ICPET 2022 2022)
Abstract
In this paper, we describe the experimental second-order coherence photons produced in SPDC. First in the experimental set up, the nonlinear BBO crystal generates the twin correlated signal and idler photons. Then for investigation of the light source nature, g2 (0) is obtained experimentally. The results show this value is less than 0.5 which verifies the generated photons are in the heralded single photon regime.
