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Dive into the research topics where Khaled A. Elsayed is active.

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Featured researches published by Khaled A. Elsayed.


Applied Optics | 2002

High-energy, efficient, 30-Hz ultraviolet laser sources for airborne ozone-lidar systems

Khaled A. Elsayed; Songsheng Chen; Larry B. Petway; Byron L. Meadows; Waverly D. Marsh; William C. Edwards; James C. Barnes; Russell J. DeYoung

Two compact, high-pulse-energy, injection-seeded, 30-Hz frequency-doubled Nd:YAG-laser-pumped Ti: sapphire lasers were developed and operated at infrared wavelengths of 867 and 900 nm. Beams with laser pulse energy >30 mJ at ultraviolet wavelengths of 289 and 300 nm were generated through a tripling of the frequencies of these Ti:sapphire lasers. This work is directed at the replacement of dye lasers for use in an airborne ozone differential absorption lidar system. The ultraviolet pulse energy at 289 and 300 nm had 27% and 31% absolute optical energy conversion efficiencies from input pulse energies at 867 and 900 nm, respectively.


Applied Optics | 2003

Compact high-pulse-energy ultraviolet laser source for ozone lidar measurements

Khaled A. Elsayed; Russell J. DeYoung; Larry B. Petway; William C. Edwards; James C. Barnes; Hani E. Elsayed-Ali

An all solid-state Ti:sapphire laser differential absorption lidar transmitter was developed. This all-solid-state laser provides a compact, robust, and highly reliable laser transmitter for potential application in differential absorption lidar measurements of atmospheric ozone. Two compact, high-energy-pulsed, and injection-seeded Ti:sapphire lasers operating at a pulse repetition frequency of 30 Hz and wavelengths of 867 and 900 nm, with M2 of 1.3, have been experimentally demonstrated and their properties compared with model results. The output pulse energy was 115 mJ at 867 nm and 105 mJ at 900 nm, with a slope efficiency of 40% and 32%, respectively. At these energies, the beam quality was good enough so that we were able to achieve 30 mJ of ultraviolet laser output at 289 and 300 nm after frequency tripling with two lithium triborate nonlinear crystals.


Proceedings of the Third International Conference on Modern Trends in Physics Research | 2011

LASER-INDUCED BREAKDOWN SPECTROSCOPY TECHNIQUE IN IDENTIFICATION OF ANCIENT CERAMICS BODIES AND GLAZES

Khaled A. Elsayed; Hisham Imam; Fatma Madkour; Galila Meheina; Yosr Gamal

In this paper we report a study on Laser Induced Breakdown Spectroscopy (LIBS) as a promising non-destructive technique for the identification of the colored glazes, and clay’s bodies of Fatimid ceramics ancient artifacts. The scientific examination of ceramics may be helpful in unraveling the history of ancient shards, particularly as the process of its production such as firing condition and temperatures. The analysis of pottery, ceramic bodies and glazed coatings is required in order to structure the conservation or restoration of a piece. Revealing the technical skills of ancient potters has been one of the most important issues for gaining a deep insight of bygone culture and also it is required in order to structure the conservation or restoration of a piece of art. LIBS measurements were carried out by focusing a Nd-YAG laser at 1064 nm with pulse width of 10 ns and 50 mJ pulse energy on the surface of the sample by a 100-mm focal length lens. The plasma emission was collected by telescopic system and transferred through a fiber to Echelle spectrometer attached to an ICCD camera. The focal spot diameter is found to be in the range of 100-150 μm. which is small enough to consider this technique as a non-destructive technique. LIBS technique clarified that each piece of archaeological objects has its own finger print. X-ray diffraction (XRD) analysis was carried out on these archaeological ceramic body samples to study raw materials such as clays, which allowed the investigation of the crystal structure and showed the changes in its structure through firing process. This provided information on the ceramic characteristic and composition of the ceramic bodies.


MODERN TRENDS IN PHYSICS RESEARCH: Second International Conference on Modern#N#Trends in Physics Research MTPR-06 | 2007

Photostability of Uranine Via Crossed‐Beam Thermal Lens Technique

M. Zein El‐Din; Khaled A. Elsayed; M. A. Harith

Uranine is a diagnostic aid in ophthalmology and used as immuno‐histological stain. Photostability study on such important compound using crossed‐beam thermal lens (TL) technique was carried out. The study is based on the photodegradation (PD) behavior and rate regarding some parameters such as the incident laser power, wavelength, modulation frequency and sample concentration. The effects of such parameters on the TL signal and PD rate are discussed in details. The rate of PD is found to be proportional to the power of the pumping laser and concentration of the sample within the investigated range. The modulation frequency is found not to influence the PD rate. The photochemical quantum yield has been measured using potassium ferrioxalate actinometry and it was found to be very low.


Laser Chemistry | 2007

Photostability of Uranine via Crossed-Beam Thermal Lens Technique

M. Zein El‐Din; Khaled A. Elsayed; S. M. Al-Sherbini; M. A. Harith

Uranine is a diagnostic aid in ophthalmology and is used as an immunohistological stain. A photostability study on this important compound using a crossed-beam thermal lens (TL) technique was carried out. The study is based on the photodegradation (PD) behavior and rate regarding some experimental parameters such as the incident laser power, wavelength, modulation frequency, and sample concentration. The effects of such parameters on the TL signal and PD rate are discussed in details. It has been found that the PD rate is proportional to the power of the pumping laser and the concentration of the sample within the investigated range. However, the modulation frequency is found not to influence the PD rate. The photochemical quantum yield has been measured using potassium ferrioxalate actinometry and it was found to be very low.


conference on lasers and electro optics | 2001

30-mJ, 30-Hz, and 300-nm ultraviolet laser source generated by a frequency-tripled Ti:sapphire laser [for DIAL]

Songsheng Chen; Larry B. Petway; Byron L. Meadows; Khaled A. Elsayed; Waverly D. Marsh; William C. Edwards; James C. Barnes

Summary form only given. A compact, frequency-tripled, and 30-Hz Ti:sapphire laser at 900 nm has been developed. The laser provides more than 30-mJ ultraviolet output pulse energy at 300 nm and will be used in an airborne ozone differential absorption lidar.


Optics and Photonics Journal | 2012

Effect of Experimental Parameters on the Fabrication of Gold Nanoparticles via Laser Ablation

Hisham Imam; Khaled A. Elsayed; M.A. Ahmed; Rania Ramdan


Spectrochimica Acta Part B: Atomic Spectroscopy | 2009

Local equivalence ratio measurements in turbulent partially premixed flames using laser-induced breakdown spectroscopy

Mohy S. Mansour; Hisham Imam; Khaled A. Elsayed; Wafaa Abbass


Optics and Laser Technology | 2013

Effect of focusing conditions and laser parameters on the fabrication of gold nanoparticles via laser ablation in liquid

Khaled A. Elsayed; Hisham Imam; M.A. Ahmed; Rania Ramadan


Optics and Laser Technology | 2012

Design and construction of Q-switched Nd:YAG laser system for LIBS measurements

Khaled A. Elsayed; Hisham Imam; Amro Harfoosh; Yasser Y. Hassebo; Yasser Elbaz; Mouayed Aziz; Mohy S. Mansour

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Yasser Y. Hassebo

City University of New York

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