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SPECTRAL WIDTH VARIATION OF ULTRASHORT LASER PULSES IN MONOMODE OPTICAL FIBERS
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Femtosecond laser pulse propagation in monomode optical fibers is demonstrated and investigated numerically (by simulations) and experimentally in this paper. A passively mode locked Nd:glass laser giving a pulse duration of about 200 fsec at 1053 nm wavelength and 120 mW average optical power with 100 MHz repetition rate is used in the experimental work. Numerical simulations are done by solving the nonlinear Schrödinger equation with the aid of Matlab program. The results show that self phase modulation (SPM) leads to compression of the spectral width from 5 nm to 2.1 nm after propagation of different optical powers (34, 43, 86 and 120 mW) in fibers of different length (5, 15, 35 m). The varying optical powers produced a varying phase shift. The output spectral width also changed with the fiber length at a given peak power.

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Publication Date
Tue Aug 01 2023
Journal Name
Iop Conference Series: Earth And Environmental Science
Monitoring Changes in the Spectral Reflectivity of Baghdad City and the Impact of the Atmospheric Elements on it using R.S and GIS
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Abstract<p>Climate change in recent years has greatly affected the distribution of ground covers. Monitoring these changes has become very easy due to the development of remote sensitivity science and the use of satellites to monitor these changes. The aim of this research is to monitor changes in the spectral reflectivity of the Baghdad governorate center for the month (March, June, September, December) of the year 2021 using remote sensing and satellite images Sentinel 2 and knowing the climate imact on them. Fifty-one samples were selected for four types of ground cover (agricultural land, water, buildings and open space) and their spectral reflectivity was calculated using satellite images. </p> ... Show More
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Publication Date
Sat May 01 2021
Journal Name
Journal Of Physics: Conference Series
Design of Step-Index Multimode Optical Fiber
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Abstract<p>In this paper, a step-index fiber with core index 1.445 5 1 7 and cladding index 1.443 1 5 7 has been designed and studied. Multimode operation is achieved by using a fiber with core radius 25 μm operating at a wavelength of 1.3 μm. The mode parameters (effective refractive index, phase constant, fractional modal power in the core and cutoff wavelength) were calculated using RP fiber calculator (PRO version 2020). The shapes of the intensity and amplitude distribution of linearly polarized guided modes were shown.</p>
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Publication Date
Tue Dec 15 2015
Journal Name
Iraqi Journal Of Laser
The Optical Limiting of Prepared Palladium Nanoparticles
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Palladium nanoparticles are produced by Polyol method. The characterization of the Pd nanoparticle has been conducted by various techniques such as SEM and AFM. The results of Pd powder showed that the particle size is directly proportional to the temperature and the reaction time. The optimum conditions for obtaining minimum nanoparticles size are 45 oC reaction temperature and 60 min reaction time and the smaller particle size achieved is equal to 25 nm. The optical limiting of smaller size nanoparticles has been studied. The palladium nanoparticles appear to be attractive candidates for optical limiting applications.

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Publication Date
Sun Jan 01 2023
Journal Name
Aip Conference Proceedings
The optical constants of amorphous silicon nanostructures
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There is of great importance to know the values of the optical constants of materials due to their relationship with the optical properties and then with their practical applications. For this reason, it was proposed to study the optical constants of amorphous silicon nanostructures (quantum well, quantum wire, and quantum dot) because of their importance in the world of optical applications. In this study, it was adopted the Herve and Vandamme (HV) model of the refractive index because it was found that this model has very good optical properties for almost all semiconductors. Also, it was carried out by applying experimental results for the energy gaps of these three nanostructures, which makes the results of the theoretical calculations

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Publication Date
Wed Apr 19 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Optical Properties of Obliquely Evaporated Manganese Films
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   The Manganese (Mn) thin films of obliquely and normal deposited were prepared by using thermal evaporation method at pressure 10-5 torr on glass substrate at room temperature. The optical properties of normal and obliquely deposited films are studied and also the effect of deposition angle on these properties. The deposition angle has great influence on the increase of the absorbance, absorption coefficient, extinction coefficient and imaginary dielectric constant and the decrease of the transmittance, reflectance, refractive index and real dielectric constant.
 

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Publication Date
Sun May 14 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
A New Design of Fractal Optical Modulation
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In this paper it was designed a new fractal optical modulation by using a new iteration of fractal function, the result was analyzed by MTF evaluation, and it compared with results of normal optical modulation.

The normal and fractal optical modulator is a circular disc which has a radius R=9cm, both of them consist of twenty sectors, ten sectors are opaque and the other ten sectors are transmitted for the light.

      The fractal optical modulator contains two patterns, the pattern two can be used to detect the target, and pattern one can be used to lock the target

The best similarity of MTF behavior for normal and fractal Reticle was evaluating the power transparent depends on the size o

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Publication Date
Mon Nov 01 2010
Journal Name
Iraqi Journal Of Physics
Optical properties of lead-bismuth cuprous glasses
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The optical transmission and absorption spectra in UV-VIS were recorded in the wavelength range 350-800 nm for different glass compositions in the system: (CuO)x (PbO)50-x (Bi2O3)50 (x=2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 20.0). Absorption coefficient {α (λ)}, optical energy gap (Eopt), refractive index (n), optical dielectric constant (ε`), Urbach energy (Ee), constant B and ratio of carrier concentration to the effective mass (N/m) have been reported. The effects of compositions of glasses on these parameters have been discussed. It has been indicated that a small compositional modification of the glasses lead to an important change in all the optical properties including non-linear behavior. The optical parameters were found to b

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Publication Date
Wed Sep 01 2021
Journal Name
Iraqi Journal Of Physics
Optical Characteristics of Vitamin D3 Soft Gel
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In this work, the linear properties of Vitamin D3-5000IU soft gel were investigated by measuring its absorption and fluorescence spectra. It was observed that there was a shift towards longer wavelength within limits (75 nm), with quantitative efficiency equal to (33.58%). The values of absorbance were used to calculate the extinction coefficient, optical refractive index, optical conductivity and optical dielectric constant values.

The non-linear properties of Vitamin D3-5000IU soft gel was also studied using the Z-Scan technique by using Neodymium-doped Yttrium Garnet (Nd: YAG) continuous laser (CW) emitting in       &n

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Publication Date
Wed Apr 23 2025
Journal Name
Journal Of Baghdad College Of Dentistry
The effect of addition of untreated and oxygen plasma treated polypropylene fibers on some properties of heat cured acrylic resin
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Background: The polymethyl methacrylate is the most reliable material for the construction of complete and partial dentures, despite satisfying esthetic demand itsuffered from having unsatisfactory properties like impact strength and transverse strength. This study was designed to improve the impact strength and transverse strength of heat cure acrylic resin by adding untreated and oxygen plasma treated polypropylene fibers and investigate the effect of this additive on some properties of acrylic resin materials. Materials and methods: Untreated and oxygen plasma treated polypropylene fibers was added to PMMA powder by weight 2.5 %. Specimens were constructed and divided into 5 groups according to the using tests; each group was subdivided

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Publication Date
Mon Jun 10 2019
Journal Name
Journal Of Global Pharma Technology
Mixed Ligand Schiff Base Complexes of Some Meta(II) Salts: Preparation. Spectral Characterization and Antibacterial Screening
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FH Ghanim, Journal of Global Pharma Technology, 2018

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