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تحسين اداء الترميز السعوي الطيفي بنظام الترميز البصري المتعدد باستخدام محزز الليف البصري نوع براغ == Performance Enhancement of SAE - OCDMA Using Fiber Bragg Grating

Author name: ابراهيم لؤي عبد الجبار
Supervisor name: تحرير صفاء منصور
General topic: Laser Science
Specific topic: Laser Applications in Electronics and Communications Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

تاثير ليزر الدايود "410 نانومتر" على البكتيريا المقاومة للمضادات الحيوية المعزولة من اخماج الحروق والجروح == The Effect of 410 nm Diode Laser on Antibiotic Resistant Bacteria Isolated from Burn and Wound Infections

Author name: منى غازي محمد
Supervisor name: امل مصطفى مكي`
General topic: Laser Science
Specific topic: Laser Applications in the Life Sciences
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

تقييم الخواص الكهربائية والحرارية لبولي ميثيل ميثاكريلات المكسو بانابيب كاربون نانونية باستخدام ليزر الياك == Evaluation of Electrical and Thermal Properties of PMMA Cladded by CNTs Using Nd : YAG Laser

Author name: ولاء عصام رسول
Supervisor name: Thaier Abid Tawfiq
General topic: Laser Science
Specific topic: Laser Applications in Mechanical Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

الخواص اللاخطية للموائع النانوية باستخدام تقنية حيود الليزر == Nanofluids Nonlinear Properties Using laser Diffraction Technique

Author name: مناف قاسم خلف
Supervisor name: مازن مانوئيل الياس
General topic: Laser Science
Specific topic: Laser Applications in Physics
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

تحليل مكونات السبائك الثلاثية باستخدام تقنية العد الفوتوني للبلازما المنتجة بالليز == Analysis of Ternary Alloys Constitutes Using Photon Counting Technique for Plasma Induced by Laser

Author name: علي زهير رضا الالوسي
Supervisor name: Mazin M. Elias | Ahmed A . Moosa
General topic: Laser Science
Specific topic: Laser Applications in Production Engineering and Metallurgy
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

دراسة معلمات البلازما المنتجة بواسطة ليزر فلوريد الكربتون خلال برنامج حاسوبي == STUDY OF KrF LASER PRODUCED PLASMA PARAMETERS VIA COMPUTER SIMULATION

Author name: سمير رحيم شهيب
Supervisor name: Al-Janabi | M. M. Elias
General topic: Laser Science
Specific topic: Laser Applications in Nuclear Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

تقييم الاجهادات المتبقية والخصائص الميكانيكية للمعادن الغير المتشابهه الملحومة بليزر ثاني اوكسيد الكاربون المستمر == Estimation of Residual Stresses and Mechanical Properties of Dissimilar Metals Welded by CW CO2 Laser

Author name: ضياء احمد صلال
Supervisor name: Adel Khaleel Mahmoud
General topic: Laser Science
Specific topic: Laser Applications in Mechanical Engineering
Degree: Doctorate
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

تاثير ليزر Q - Switched Nd : YAG على بعض عوامل الفوعه لبكترياPseudomonas aeruginosa بوجود سفرانين O == Effect of Q - Switched Nd : YAG Laser on Some Virulence Factors of Pseudomonas aeruginosa in The Presence of Safranin O

Author name: حنان محمد عباس الجنابي
Supervisor name: امل مصطفى مكي
General topic: Laser Science
Specific topic: Laser Applications in the Life Sciences
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

التاثير القاتل لليزر ثاني اوكسيد الكاربون على اصابه ماحول زرعه السن : دراسه خارج الجسم == Bactericidal Effect of CO2 Laser on Peri - Implant Infection (in Vitro Study

Author name: بيداء فليح حمزة
Supervisor name: علي شكر محمود | اسراء حسن عبدعلي
General topic: Laser Science
Specific topic: Laser Applications in Medicine - Dentistry
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

الاعتبارات التصميمية لتكيف الليزر القرصي الى ماكنة تحكم رقمي مبرمج == Design Considerations for Disc Laser adaptation to CNC Machine

Author name: يوسف حربي عبد الامير الاسدي
Supervisor name: Khalil Ibrahim Hajim
General topic: Laser Science
Specific topic: Laser Applications in Mechanical Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

دراسة مصدر اشعاع قوس التفريغ الكهربائي المعزز بالليزر من القصدير السائل في المدى الطيفي للاشعة فوق البنفسجية القصوى == INVESTIGATION OF A LASER ASSISTED VACUUM ARC RADIATION SOURCE OF LIQUID TIN IN THE EUV SPECTRAL RANGE

Author name: وسام حسن مهدي العجيلي
Supervisor name: خليل ابراهيم حاجم
General topic: Laser Science
Specific topic: Laser Applications in Physics
Degree: Doctorate
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

مرشح ضوئي حزمي المرور متعدد التنغيم باستخدام الالياف البلورية الفوتونية == All - optical tunable bandpass filter using Photonic crystal fiber

Author name: ميثم صبري جابر
Supervisor name: عبد الهادي مطشر الجنابي
General topic: Laser Science
Specific topic: Laser Applications in Electronics and Communications Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

دراسة اداء جهاز مرشح الليف البصري ذو الحزمة الضيقة باستخدام محززات براك لليف البصري == Study the Performance of Implemented Narrow Band Optical Fiber Filter Using FBGs

Author name: مناف صالح مجيد
General topic: Laser Science
Specific topic: Laser Applications in Physics
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

تاثير ليزر ثنائي اوكسيد الكربون المجزئ على خشونة السطح وارتباط زركونيوم السيراميك مع الاسمنت الراتنج == Effect of Fractional CO2 Laser on the Surface Roughness and Bonding of Zirconium Ceramic to Resin Cement

Author name: لمى ابراهيم محمد علي
Supervisor name: حسين على جواد
General topic: Laser Science
Specific topic: Laser Applications in Medicine - Dentistry
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

توليد الموجه المثالية باستخدام محزز براغ الليفي == Soliton Generation in Fiber BraggGrating

Author name: ليث طارق محمد
Supervisor name: تحرير صفاء منصور
General topic: Laser Science
Specific topic: Laser Applications in Electronics and Communications Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:

تنفيذ البوابة اكس اور بصريا بالكامل لمنظومات الاتصالات البصرية == Implementation of All Optical Exclusive - OR Gate for Optical Communication Systems

Author name: ياسمين سلمان كاظم
General topic: Laser Science
Specific topic: Laser Applications in Electronics and Communications Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:
Abstract: One of the most important techniques used to realize logic gates in optical networks is by all - optical signal processing.The most two important problems of electronic signal processing are high propagation loss of electronic signals and the high cost of the high speed electronics. Accordingly, these reasons led to converting to optical domain at higher frequencies (≥ 10 ????????/????) .The goal of this work is to implement all optical logic gates specifically exclusive - OR gate. Exclusive - OR gate have an important role in data encryption, parity checking, data encoding, bit pattern generation and matching, addressing, header recognition and many more applications. In this work an all - optical exclusive - OR logic function was achieved by a simulation software and implementing an experiment.In the simulation work, the exclusive - OR function was implemental by using a highly nonlinear fiber with a fiber nonlinear coefficient of 9.1 ????−1????????−1 , 0.135 km length non - degenerate with four wave mixing process and a NRZ - DPSK 10 GB/s signals.Experimentally the exclusive - OR function was implemented by using a highly non fiber with a fiber nonlinear coefficient of 10 ????−1????????−1and a 1 km length with bidirectional degenerate four wave mixing process. The optical signals that were used for the operation of the exclusive - OR function were NRZ - DPSK 40 GB/s signals. Results showed an exclusive - OR function associated with clear eye diagrams. In addition to that, exclusive - NOR function was also obtained experimentally in addition of these four maxterms (A + B, ????̅+ B, A + ???? ̅ and ????̅ +???? ̅ ).

تاثير ليزر النودميوم ياك وبيبتيدات الفوسفات الجبنية - فوسفات الكالسيوم الغير متبلرة مع الفلوريد على ازالة تمعدن مينا الاسنان في دراسة مختبرية == The Effect of Nd : YAG Laser and Casein - Phosphor - Peptide - Amorphous Calcium Phosphate with Fluoride on Dental Enamel De - mineralization : In vitro study

Author name: هبة عصام عبد الوهاب
Supervisor name: علي شكر محمود
General topic: Laser Science
Specific topic: Laser Applications in Medicine - Dentistry
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:
Abstract: New approaches for caries prevention by using lasers effect combined remineralizing agent providing calcium and phosphate in addition to flouride for increasing the tooth mineral resistance needed. The aim of this study is to evaluate a new treatment modality to decrease dental enamel dissolution via combing the effect of pulsed Nd : YAG laser (1064 nm) and MI plus paste (CPP - ACP containing sodium fluoride ) regarding the tooth pulp chamber temperature elevation, calcium concentration dissolute from enamel surfaces and the dental enamel absorption of methylene blue stain by assessing (R,G,B)values .Eighty human permanent premolar were used in this study, sixty of them were randomly divided into six groups of 10 specimens. The negative control group A received no treatment, and the positive control group B the MI plus paste was applied without laser irradiation. For the groups C, D, E and F the pulsed Nd : YAG (1064 nm) laser was used in two energy settings. The lower laser dose setting at (0.6W, 60 mJ )without and with the MI plus paste for the groups C and D respectively and the higher laser energy setting at (1.7W, 170 mJ )with and without the MI plus paste for the groups E and F respectively.Twenty teeth were used to asses s the temperature elevation during irradiation with laser using a K - type thermocouple at 37 ± 0.5 ̊C, ten teeth exposed to the lower laser energy settings and ten for the higher laser energy settings.A circular window (4 mm radius) marked area on buccal surfaces of the 60 samples after they had been coated with three layer of nail varnish to exposed to the Nd : YAG laser irradiation, and then the samples incubated in 3ml acidic solution of acetate buffer of (0.1M/L) with a pH value of 4.5 for 48 hours . The acidly etched samples removed from the acidic solution after they had been washed from acid they immersed in a 2% solution of methylene blue dye to measure the (R,G,B) values to indicted the affinity of sample surfaces for absorbing methylene blue stain that indicate the surface demineralization . Results of temperature test +showed that the maximum temperature increases for group E (4.7 Co) was very high significant difference (p<0.05) over that of groups C (2.5 Co).The atomic absorption photometry test results showed that groups C, and D were statistically different compared to the groups A and B (p<0.001) in the reduction of calcium dissolution, with a reduction percentage for groups C and D of 25.7% and 33.34% respectively compared to group A, with 21.75% and 29.8 % for groups C and D respectively in comparison to group B. While Groups E and F shown nonsignificant reduction in calcium dissolution compared to control groups.The (R,G,B)s value test showed that groups C and D having lower affinity to absorb methylene blue stain, and they are statically significant different compared to the groups A and B .while groups E and F showing a higher affinity to absorb methylene blue stain compared to control groups. In conclusion the both laser irradiation settings energy (60mJ, 0.6 W,0.12 J/cm2),(170mJ,1.7W,0.34J/cm2) are safe for the vitality of the dental pulp, and when both settings combined with the Phosphor - Peptide - Amorphous Calcium Phosphate with Fluoride ,the results showing significant reduction of dental enamel de - mineralization and lower affinity for methylene blue absorption that although indicate increasing dental enamel resistance to demineralization for the groups of (60mJ, 0.6 W,0.12 J/cm2) laser irradiation settings.

تاثير المعلمات المختلفة لليزر الليف على تعرية الصبغ البوليمري من على سطح سبيكة الالمنيوم نوع 5005A == Effect of Different Fiber Laser Parameters on Stripping of Polymer Paint from Surface of 5005A Aluminum Alloy

Author name: هالة عبود جاسم
General topic: Laser Science
Specific topic: Laser Applications in Mechanical Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:
Abstract: This study provides details of the use of laser as an alternative method to the conventional ones to remove (20) μm thickness of polyester paint from EN AW - 5005A Aluminum alloy, the laser paint stripping process performed by ytterbium fiber laser with a wavelength (1064) nm .Sets of experiments curried out in order to reach to the most suitable parameters for the process, at the first set different levels of energies used from 0.0425 mJ to 1.12 mJ, nine lines of holes accomplished by laser. The holes diameters and the depth at each energy measured in this experiment. At two different pulse repetition rates (20, 50) KHz two sets of experiments done. At the first set the effect of laser energy (0.1565, 0.73, 1.12)mJ also the overlap percent (25%, 50%, 75%) have been studied at five number of passes, the parameters of the process settled by the overlap equations, the effect of the overlap percent on the total time of machining and the material removal rate at different levels of energy also investigated, it’s found that the best energy to work with is 0.1565mJ with one and two passes.The second set of experiments done at 0.1565mJ with a wider range of overlap percent from 25% to 75% increase by five. The removal depth and the behavior of surface roughness determined by Focus Variation Microscopy (FVM) also Scanning Electron Microscope used to analyze the radiated area. It’s found that the best results obtained at 50 % overlap when the laser passes one time on the material.Laser Induced Breakdown Spectrometer (LIBS) used as a method for monitoring and controlling the paint stripping process in order to accomplish the process and ablate only the paint layer without ablating the substrate, for the paint and the substrate (LIBS) spectrum obtained and used to distinguish between the paint layer and the Aluminum substrate.

قياس وتحليل الخسائر لموجات الموجع ذوات الفتحة المصنعة من سليكون على عازل == Measurements and Analysis of The Losses for Fabricated SOI Slot Waveguides

Author name: ميثم نعيم صالح
Supervisor name: مازن مانوئيل الياس
General topic: Laser Science
Specific topic: Laser Applications in Electronics and Communications Engineering
Degree: Doctorate
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:
Abstract: An interesting silicon photonics component is the slot waveguide. The discontinuity of the normal component of the displacement vector can be used to affect guiding of the majority of the electric field energy in a narrow low index gap when the field is polarized parallel to the silicon surface, that is, perpendicular to the silicon confining walls. By infiltrating nonlinear material into such a gap, one can simultaneously confine electric and optical fields achieving a high efficient optical modulation or switching that is becoming more desirable on optical communication. An array of 200 Silicon - on - Insulator (SOI) slot waveguide devices of varying slot widths, ribs widths, taper lengths and slot lengths are fabricated in each cell of a wafer fabricated at a commercial foundry. The cells are cleaved into individual chips after fabrication. Some chips are coated with thin films of polymers that fully infiltrated the slots. Measurements that consisted on spectral loss are made on the grating coupler waveguide devices of both coated and uncoated chips. Individual devices exhibited insertion losses varying from several dB up to values so great that the response is below the noise floor of the optical spectrum analyzer employed as a receiver. The chips that failed in the transmission test are primarily uncoated ones. Nominally identical devices on different chips exhibited nominally identical behavior. A commercial software program is used to simulate each of the structures that is included in the 200 devices test. The simulations are seen to show a degree of qualitative agreement with the experimental results. Comparison of the experimental measurements and the simulation results indicates that the loss inherent in a slot waveguide is quite low. Near loss free couplers from ridges to slots are achievable in case of coated devices, whereas the situation is different in case of uncoateddevices where a lot of energy is dissipated through the substrate. Use of a surface roughness model indicates that the excess loss that slots exhibit with respect to a ridge mode counterpart arise almost solely from surface scattering off the surface roughness. The increased loss in the case of the slot guide arises from the higher electromagnetic energy density at the surface of the guide due to the electric field discontinuity that is employed as a guidance mechanism in slot modes in contradistinction to ridge modes that are index - guided. Conclusions include some speculation as to the limits on the loss that can be achieved by variation the design of slot guides without any improvement in surface roughness over what is now available with fabrication in commercial foundries.

محزز الليف البصري نوع براغ لتحسس الحرارة والضغط == FIBER BRAGG GRATING FOR TEMPERATURE AND PRESSURE SENSING

Author name: فهد محمد عبد الحسين
Supervisor name: تحرير صفاء منصور
General topic: Laser Science
Specific topic: Laser Applications in Electronics and Communications Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:
Abstract: Nowadays, the modern trends in optical sensing are to build simultaneous measurements sensors. In this work two schemes for simultaneous measurements sensors are presented. The first one is with dual FBGs peaks. Every FBG acts as sensing head. The first peak was used for temperature sensing and the obtained sensitivity is 10 pm/˚C and the second peak was used for temperature and pressure measurements with sensitivities 9.2 pm/˚C and 67 pm/ bar for temperature and pressure respectively.The other scheme consists of two sensing heads fabricated in the lab. The first sensing head is the Fabry - Perot interferometer which was used for load and strain measurements by controlling the size of its cavity reached to minimum value in micro scale (30). The sensitivity was increased to 4.07 nm/ N and 5.11 pm/ μɛ for load and strain respectively. This sensitivity for load is the highest that was recorded by micro cavity where previous works were reached to 1.37 nm/N. The second sensing head made by inscribing Bragg gratings inside the core of All Solid Photonic Band - Gap fiber toenhance its sensitivity that reached to 13.7 pm/˚C and 0.7 pm/μɛ for temperature and strain respectively which is more sensitive than previous works of our group in the institute that reached to 10 pm/˚C and 0.66 pm/μɛ for temperature and strain respectively. The obtained temperature sensitivity for the Bragg gratings is higher than previous work for Bragg gratings inscribed on All Solid Photonic Band - Gap Fiber where it was 12.04 pm/˚C.Strain sensitivities were almost the same.

التحقق عمليا من بروتوكول البينغ بونغ

Author name: علاء جبار جمعة
Supervisor name: شيلان خسرو توفيق
General topic: Laser Science
Specific topic: Laser Applications in Electronics and Communications Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:
Abstract: Quantum cryptography uses basic laws of quantum physics to guarantee secure key exchange. The key can be used with unprecedented confidence in any classic cryptographic protocol, where it increases the security to the maximum achievable value. The goal of this work is to encrypt the message directly without need to generate the secure key by using the modified Ping - Pong Protocol. A quantum cryptography system based on Modified Ping - Pong Protocol was designed and implemented for the first time. A polarization - entangled photons were generated by a source using PPKTP crystal inside a polarization Sagnac interferometer at telecom wavelength 1550 nm and a fiber length of 15 Km. In this experiment, Bob prepares entangled photons, sends one photon to Alice by optical fiber to perform one out of four operators according to the message. The modulated photon is sent back to Bob. Then the Bell’s state measurement is applied to extract the message according to the Alice’s coding. The HOM - dip of the two - photon interference was verified to guarantee perfect system performance. The final results showed the switching between the Bell’s states, |????+⟩ and |????−⟩ as the phase of the phase modulator was changed by Alice achieving an acceptable coincidence count of about 625 counts per 30s. These results proves also two photon interference needed to test Bell’s enquality.

تحسين خصائص سطح سبيكة الالمنيوم باستخدام الاكساء بالليزر بانابيب كاربون نانوية مزدوجة الجدار ونابيب كاربون نانوية متعددة الجدار == Enhancement of Al 6061 - T6 Alloy Surface Properties using Laser Cladding with DWCNTs and MWCNTs

Author name: حسنين مجيد حسين
General topic: Laser Science
Specific topic: Laser Applications in Mechanical Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:
Abstract: Industrial applications of nanomaterial in particular carbon nanotubes (CNTs) have increased from various viewpoints, such as, high performance, energy saving, cost saving, and environmental concerns. Laser cladding technique has been used successfully to modify the surface properties of materials, i.e., improving their wear and corrosion resistance. This work involves cladding aluminum alloy (Al 6061 T6) with different types of carbon nanotubes (multi - walled carbon nanotubes (MWCNTs) and double walledcarbon nanotubes (DWCNTs)) by an automated pulsed Nd : YAG laser. This was achieved by controlling selected cladding parameters whic h are laser power, pulse duration, and working frequency. The experimental investigation included microhardness, energy dispersive X - ray, corrosion resistance and microstructure topography by scanning electron microscope. At the beginning, fifteen cladded samples divided into three groups were investigated to choose the best laserparameters for the process to have almost the best homogeneous clad layer. Group one; five levels of peak power (2.7, 2.9, 3.1, 3.3, and 3.5) kW respectively where varied versus fixed pulse duration of 16 ms, working frequency of 1.5 Hz, and scanning speed of 0.5mm/s. Group two; five levels of pulse duration (12, 14, 16, 18 and 20) ms respectively where varied versus fixed peak power of 3.1 kW, working frequency of 1.5Hz, and scanning speed of 0.5mm/s. Group three; five levels of working frequency of (1.1, 1.3, 1.5, 1.7, and 1.9) Hz respectively where varied versus fixed peak power of 3.1 kW, pulse duration of 16 ms and scanning speed of 0.5 mm/s. The investigation shows that the optimum estimated laser parameters for achieving the best results at spot diameter of 3 mm were (peak power of 3.1 kW, pulse duration of 16 ms (3 ms as preheating and 13 ms as the main action time of the pulse) and working frequency of 1.5 Hz.The executed process in this work was computationally modeled using commercial multiphysics finite element analysis (FEA) software package ANSYS® Release 11 to simulating the virtual environment of laser cladding process to determine the temperature distribution in three - dimensional (3D) analysis. Results indicated that laser cladding of Al 6061 T6 using DWCNTs enhanced three of the most important of surface properties which are hardness, abrasive wear resistance and corrosion resistance more than did the MWCNTs. The distribution of the MWCNTs on the surface of Al 6061 T6 is better than that for the DWCNTs but its penetration is less. Theoretical results show that the diffusion played an important role in the cladding process.

الليف البلوري الفوتوني لاستشعار المجال المغناطيسي == Photonic crystal fiber magnetic sensor

Author name: احمد عدنان محمد
Supervisor name: عبد الهادي مطشر الجنابي
General topic: Laser Science
Specific topic: Laser Applications in Electronics and Communications Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:
Abstract: Photonic crystal fiber (PCF) is widely used for sensing applications. In this work, magnetic sensor based on solid core - PCFs for sensing magnetic field was presented. The general structure of the sensor applied is by splicing short lengths of PCF (LMA - 10) with conventional single mode fiber (SMF - 28) in one side and using free space connector from other side. A laser diode with different wavelengths (850, 1060 and 1300 nm) has been used as a light source, where a high sensitive optical spectrum analyzer (OSA) was used to monitor and record the transmitted/reflected spectra.The present work demonstrates the results of the infiltration of the air holes for the PCFs by fluids instead of air. For magnetic sensing, the magnetic fluids being used were prepared and standard ????????3????4 to infiltrate the air holes for the solid core PCF (LMA - 10) which leads to change in the effective refractive index of the PCF, which in turn affects the transmission of the laser inside the PCF due to the value of the refractive indices of the magnetic fluids. The experiments show that the power of transmissionspectrum of the laser had decreased after infiltration without any change in central wavelength of the laser diode the reason is that after PCF air holes infiltration, the effective refractive index has been changed but still within total internal reflectionwhich leads to loss of some fundamental modes, in turn leads to decrease the power of transmission spectrum. The decrease of the transmitted power in the case of standard has been higher than it in the case of prepared ????????3????4 because of the differencein concentration between standard and prepared magnetic fluids. The power of transmission spectrum after PCF infiltration will be increased with increasing magnetic field. Higher sensitivity has been obtained that reached 5.809 nW/mT which consideredhigher than previously published works on PCF magnetic sensors.

التحقق من تاثير عدم استقرارية بلاتو - رايلي في عملية سحب ليف شبه المواد انديوم - بوليمر == Investigation of the influence of the Plateau - Rayleigh instability in fibre drawn indium - PMMA metamaterial

Author name: احمد عبد الكريم علي
Supervisor name: عبد الهادي مطشر الجنابي
General topic: Laser Science
Specific topic: Laser Applications in Electronics and Communications Engineering
Degree: Doctorate
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
First pages:
Abstract: Metamaterial is a synthetic composite material with a structure such that it exhibits properties not usually found in natural materials. Fibre drawing method has been used in producing Poly - methyl methacrylate (PMMA) - indium wires metamaterials. PMMA and indium are having relatively the same glass transition temperature making them suitable for co - drawing. The fiber filaments must be drawn to smaller diameters to shift the metamaterials response to higher frequency. At these dimensions the metal filaments inside the fiber become unstable and break - up at random intervals. This instability is due to a phenomenon known as the Plateau - Rayleigh InstabilityWell known Tomotika model for the growth in the varicosity in the surface of fluid extended inside another fluid was modified to describe the fluctuations (instability) of inner core diameter for metamaterials drawing inside radiative furnace. Modified Tomotika model was used to investigate the instability growth of the indium wire diameter produced by co - drawing of indium metal embedded in a PMMA polymer.The critical parameter for the wire breaks is the wavelength of perturbations. A MATLAB model was used to describe a small drawing ratio (neglecting the wavelength of fluctuations effect). The experimental and modeling results are almost match when a very small temperature variation occurred. So the observed fluctuations in diameter can be reconciled with the Plateau - Rayleigh instability.For larger fluctuations (large drawing ratio) the wavelength of fluctuations was analyzed and sequential breakup on different length scales was observed. We infer limits to wire dimensions that can beachieved using the chosen material system and identify a path for extending drawing methods to fabricate smaller wires.Finally, simulation for deep subwavelength wave propagation inside wire metamaterials depending on the unit cell manipulation was performed. CST microwave studio software had been used to simulate wave propagation inside linear and 90o corner waveguide as well as equal arms beam splitter (50/50). It’s applicable to waveguiding 40cm wavelength in about 2.4 cm waveguide.

التلوين المستحث بليزر الليف للتيتانيوم العالي النقاء == Fiber Laser Induced Colouration of High Purity Titanium

Author name: نور ياسر حسون حمادي
General topic: Laser Science
Specific topic: Laser Applications in Mechanical Engineering
Degree: Master
University: University of Baghdad - Laser Institute For Postgraduate Studies
Language: English
University location: Baghdad
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