Showing 5 results for mansour
Mina Eslamifar, Nastaran Mansour,
Volume 6, Issue 1 (International Journal of Optics and Photonics (IJOP) Vol 6, No 1, Winter-Spring 2012)
Abstract
In this work, thermo-optical properties of gold nanoparticle colloids are studied using continuous wave (CW) laser irradiation at 532 nm. The nanoparticle colloids are fabricated by 18 ns pulsed laser ablation of pure gold plate in the distilled water. The formation of the nanoparticles has been evidenced by optical absorption spectra and transmission electron microscopy. The nonlinear optical properties of gold nanoparticles colloids are investigated by closed Z-scan under irradiation of a low power CW laser. It will be shown that the thermal lens model is in excellent agreement with the experimental results of samples. The aperture-limitted optical limiters based on the nonlinear refraction of colloidal solution are presented. The tunability of limiting threshold of optical limiters can be accomplished by engineering of the experimental geometry.
Esmat Jafari, Mohammad Ali Mansouri-Birjandi,
Volume 12, Issue 2 (International Journal of Optics and Photonics (IJOP) Vol 12, No 2, Summer-Fall 2018)
Abstract
In this paper, a new structure is provided for the dispersion compensating photonic crystal fibers in order to broaden the chromatic dispersion and increase the dispersion compensating capability in a wide wavelength range. In the structure, putting elliptical holes in the first ring of the inner core clad of a dispersion compensating fiber of the hexagonal lattice, increases the wavelength range of the dispersion compensation, and causes this fiber to have the capability of dispersion compensation in the whole E to U telecommunication bands. In this fiber, the minimal dispersion will be -1006 ps/(nm.km) at the 1.68 μm wavelength and at the 1.55 μm wavelength the dispersion coefficient will be -710 ps/(nm.km). The simulations are all done using the finite difference time domain numerical method.
Ehsan Naghizadeh Alamdari, Mostafa Sahrai, Reza Kheradmand, Mansour Eslami,
Volume 16, Issue 1 (Winter-Spring 2022)
Abstract
Cavity Solitons (CSs) in an injected broad-area semiconductor laser with intracavity saturable absorber exhibit phase noise free and high-contrast intensity oscillations in period-one dynamical state. The continuous-wave periodic intensity oscillation of the CSs has a frequency well beyond the relaxation oscillation frequency and can be regarded as a photonic microwave source. Here we numerically investigate the effect of linewidth enhancement factor on the dynamical characteristics of CSs in the period-one regime. We show that in a fixed injection amplitude, it has a key role in shifting the oscillation frequencies of the period-one CSs and that its effects strongly depend on the cavity detuning value.
Ehsan Adibnia, Majid Ghadrdan, Mohammad Ali Mansouri-Birjandi,
Volume 17, Issue 2 (Summer-Fall 2023)
Abstract
This research addresses the complexities and inefficiencies encountered in fabricating fiber Bragg gratings (FBGs), which are crucial for applications in optical communications, lasers, and sensors. The core challenge lies in the intricate relationship between fabrication parameters and the FBG's physical properties, making optimization time-consuming. To circumvent these obstacles, the study introduces an artificial intelligence-based approach, utilizing a neural network to predict FBG physical parameters from transmission spectra, thereby streamlining the fabrication process. The neural network demonstrated exceptional predictive accuracy, significantly reducing the parameter prediction time from days to seconds. This advancement offers a promising avenue for enhancing the efficiency and precision of FBG sensor design and fabrication. The research not only showcases the potential of artificial intelligence in revolutionizing FBG production but also contributes to the broader field of optical technology by facilitating more rapid and informed design decisions, ultimately paving the way for developing more sophisticated and sensitive FBG-based applications.
Zahra Ahmadimanesh, Babak Jaleh, Mahtab Eslamipanah, Milad Daneshnazar, Hassan Hassan Sepehrmansourie, Mohammad Ali Zolfigol,
Volume 17, Issue 2 (Summer-Fall 2023)
Abstract
In this research, palladium nanoparticles (Pd NPs) were first synthesized using laser ablation in the deionized (DI) water environment. Also, metal-organic framework (MOF) was produced using the solvothermal method at a temperature of 150°C. To accumulate Pd NPs on the synthesized MOF, ultrasonic and magnetic stirring methods were used. Different analytical methods were used to investigate the structure and morphology of the synthesized nanocomposite. Also, the sensitivity of the synthesized nanocomposite to ethanol and methanol organic vapors was investigated. The results showed an increase in the response of the MOF in the presence of nanoparticles.
