Tarek Mohamed

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Verified

Tarek verified their affiliation via an institutional email.

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• PhD, Stockholm University, 2003
• Vice President at Beni-Suef University

Breast cancer is the second most common cancer globally and the leading cause of cancer-related deaths in women. Current treatments, such as chemotherapy and surgery, often have side effects and can lead to drug resistance. Developing new treatments that specifically target cancer cells while minimizing side effects is essential. Combining traditio...

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disorder characterized by joint damage and persistent pain. Despite advances in treatment, there is currently no definitive cure for RA, and the side effects of available medications often limit their long-term use. Therefore, this study investigated the therapeutic potential of femtose...

We present the results of a simulation of the dispersion of femtosecond laser pulses in a multipass cell containing methane gas at atmospheric pressure. The multipass cell with a base length of 1 m has highly reflecting mirrors in a confocal arrangement to achieve long optical paths of 600 m. The femtosecond laser pulse is produced by different fem...

Breast cancer ranks as the second most widespread form of cancer globally. Currently, combination therapy is being actively employed in clinical practice to augment the efficiency of anticancer treatment. Hence, the objective of this study was to assess the therapeutic efficacy of a combination of femtosecond laser‐based PDT utilizing two distinct...

Due to their unique features, perylenediimide derivatives attracted much interest in optical and optoelectronic applications. Along this line, we report herein the optical nonlinearity of a water-soluble perylenediimide derivative , namely, N, N'-di(2-(trimethylammonium iodide)ethylene) perylenediimide (TAIPDI), using a femto-second (fs) laser puls...

In recent years, hexagonal boron nitride nanosheets (h-BNNs) have gained attention due to their outstanding optical properties. However, researchers have yet to extensively investigate the nonlinear optical (NLO) properties of such new materials. In the present study, NLO properties of h-BNNs were investigated for the first time, to the best of our...

In this report, the nonlinear optical (NLO) properties of titanium dioxide nanoparticles (TiO2 NPs) have been explored experimentally using femtosecond laser light along with the Z-scan approach. The synthesis of TiO2 NPs was carried out in distilled water through nanosecond second harmonic Nd:YAG laser ablation. Characterization of the TiO2 NPs co...

In this work, the nonlinear optical (NLO) properties of CuO nanoparticles (CuO NPs) were studied experimentally using the pulsed laser ablation (PLA) technique. A nanosecond Nd: YAG laser was employed as the ablation excitation source to create CuO NPs in distilled water. Various CuO NPs samples were prepared at ablation periods of 20, 30, and 40 m...

One environmentally friendly technique for creating colloids of nanoparticles is pulsed laser ablation in liquid, which stands out for its ability to create nanoparticles free of contamination without the use of hazardous chemicals. In the present work, A Q-Switched Nanosecond Nd: YAG laser was utilized to precisely produce colloidal copper oxide n...

In this study, the Z-scan technique was used to investigate the nonlinear optical properties of nickel oxide (NiO) thin films of various thicknesses. Direct current (DC) sputtering was used to deposit single-phase NiO thin films with thicknesses of 280, 350, and 470 nm onto a soda-lime glass substrate. The film structure was measured using X-ray di...

Water makes up around 60 % of the body, making it essential to all body systems and crucial to human health and survival. The lack of clean drinking water is currently a problem in many different countries. While there are several approaches for disinfecting drinking water, including the widely used ozonation, UV irradiation, and chlorination proce...

Metallic nanoparticles have gained attention in technological fields, particularly photonics. The creation of silver/gold (Ag/Au) alloy NPs upon laser exposure of an assembly of these NPs was described. First, using the Nd: YAG pulsed laser ablation’s second harmonic at the same average power and exposure time, Ag and Au NPs in distilled water were...

Radio-over-fiber (RoF) systems have recently attracted a lot of attention as a way to integrate wireless and optical systems to enhance communication capacity and keep up with high-speed transmission services. Semiconductor lasers (SLs) play an important role in the development of analog RoF systems due to their high bandwidth. However, when the SL...

Female breast cancer is the most diagnosed cancer globally, and it poses a serious global health threat. Traditional cancer treatments have several undesirable side effects. The most effective therapy for treating breast cancer is doxorubicin (Adriamycin), but it has severe side effects, so developing better therapies for breast cancer is necessary...

Enterococcus faecalis is among the most resistant bacteria found in infected root canals. The demand for cutting-edge disinfection methods has rekindled research on photoinactivation with visible light. This study investigated the bactericidal activity of femtosecond laser irradiation against vancomycin-resistant Enterococcus faecalis V583 (VRE). T...

The existence of pathogenic microorganisms is a significant contributor to high morbidity rates in both developed and developing countries. Numerous human diseases have been related to Escherichia coli and Enterococcus faecalis. Fast diagnosis of these bacteria is crucial for limiting the progress of the associated diseases. The current study inves...

The present study investigate whether diode laser activation of two nanoparticle herbal irrigants affect Enterococcus faecalis (E.faecalis) biofilm and Candida albicans (C. albicans) compared with photodynamic therapy (PDT) utilizing methelyene blue as photosensitizer (PS). Material and methods: sixty single rooted teeth had undergo mechanical prep...

Sodium hypochlorite irrigant (NaOCl) has many disadvantages although it possesses antibacterial activity and having the capability to disband the pulp tissue. The aim of this study was to compare the effect of two nanoparticle herbal irrigants to that of Sodium hypochlorite (NaOCl) on Enterococcus faecalis and Candida albicans. Sixty single-rooted...

Optical fiber networks are considered an attractive solution for increasing data transmission rates in communication systems. Laser diodes (LDs) are common light sources used to transform electrical signals into optical ones in optical fiber systems. The direct modulation of LDs is preferred as a data transmission technique to decrease power consum...

The effect of alpha particle radiation on nonlinear optical properties of poly(allyl diglycol carbonate) (CR-39) polymer has been investigated using the Z-scan technique. CR-39 polymers were exposed to alpha particles at different doses: 23.7 and 47.5 Gy. Alpha particles cause significant optical and chemical changes in the polymer CR-39. Data from...

Medical diagnosis usually requires blood analysis of various biomarkers which are essential for disease detection and health status monitoring. Cardiac troponin 1 (cTn1) is a protein member of the cardiac troponin complex used for the diagnosis of several pathologies associated with cardiomyocyte necrosis. Laser-induced fluorescence (LIF) is a te...

To shed the light about the effect of the linkers of the small organic molecules on their optical properties, we examine herein the linear, and nonlinear optical properties of the two easy synthesized push-pull compounds 1 and 2 bearing similar donor and acceptor moieties based on stilbene derivatives, but differ in the spacer group, namely 4-cyano...

Parasitic Eimeria species infection is a severe disease in the poultry industry and a major cause of coccidiosis and disease-engendered financial losses. Increasing resistance to drug-based treatment presents a significant problem, as does the use of disinfectants to sanitize poultry farms, because of increasing oocyst resistance to chemical interv...

The nonlinear absorption (NLA) properties of ITO thin films were performed by utilizing femtosecond (100 fs), a high-repetition rate (80 MHz), and near-infrared (NIR) (750-820 nm) laser pulses. A radio frequency (RF) magnetron sputtering system was used to prepare ITO thin films of two different thicknesses. A scanning electron microscope was used...

Introduction: The purpose of this study is to investigate and compare the effects of the antimicrobial agents Moringa oleifera and bioactive glass nanoparticles activated by femtosecond laser light on the biomimetic dentin remineralization using teeth having carious dentin ICDAS code 3. Methods and Materials: A total of 27 dentin surface samples we...

Worldwide, the most frequently diagnosed cancer is female breast cancer, and it poses a serious global health threat. Traditional cancer therapies are associated with various side effects, so developing better therapies for breast cancer is necessary, such as laser therapy which could be a promising treatment option. The aim of the current study wa...

The nonlinear absorption (NLA) properties of ITO thin films were performed by utilizing femtosecond (100 fs), a high-repetition rate (80 MHz), and near-infrared (NIR) (750–820 nm) laser pulses. A radio frequency (RF) magnetron sputtering system was used to prepare ITO thin films of two different thicknesses. A scanning electron microscope (SEM) was...

We present a numerical simulation study on the effect of the linewidth enhancement factor (α) of semiconductor laser and dispersion management methods of optical fibers on the performance of 40-Gb/s directly-modulated fiber links and their application in WDM systems. The dispersion management methods include the use of non-zero dispersion-shifted f...

Third-order nonlinear optical (NLO) properties of indium tin oxide (ITO) thin film were studied using high repetition rate (80 MHz), femtosecond (100 fs), and near-infrared (NIR) (750-820 nm) laser pulses. An ITO thin film was prepared using an RF magnetron sputtering system. The film thickness was determined using a scanning electron microscope (S...

We present numerical modeling and simulation on the effects of standard single-mode fiber (SSMF) properties and different dispersion management approaches on the distortions of laser diode. These distortions are associated with the two-tone modulation of laser diode for use in radio over fiber systems. The fiber properties include attenuation and d...

The nonlinear optical properties of zinc oxide nanoparticles (ZnONPs) in distilled water were measured using a femtosecond laser and the Z-scan technique. The ZnONPs colloids were created by the ablation of zinc bulk in distilled water with a 532 nm Nd: YAG laser. Transmission electron microscopy, an ultraviolet-visible spectrophotometer, and atomi...

We studied the antimicrobial effect of gold quantum dots (AuQDs), femtosecond laser irradiation, and the combined effect of laser irradiation and AuQD treatment against common infectious eye pathogens. The INSPIRE HF100 laser system (Spectra Physics) provided a femtosecond laser, which was pumped by a mode-locked femtosecond Ti: sapphire laser MAI...

We reported experimental results from investigations that employed the Z-scan method to explore the dependence of silver nanoparticles’ (AgNPs) nonlinear optical properties on the excitation wavelength, AgNP concentration, and size. Using a 532 nm Nd: YAG laser beam at 100 mJ/pulse for different ablation times, AgNPs were synthesized from a silver...

Liver fibrosis is the excessive accumulation of extracellular matrix (ECM) proteins that occurs in chronic liver injury. Inflammation and oxidative stress play a key role in fibrogenesis which can develop into cirrhosis and carcinoma. Low-level laser therapy (LLLT) has promising therapeutic effects against fibrogenesis; however, the specific underl...

The unusual physical, chemical, and biological features of nanoparticles have sparked considerable attention in the ophthalmological applications. This study reports the synthesis and characterization of zinc oxide nanoparticles (ZnONPs) using laser-ablation at 100 mJ with different ablation times. The synthesized ZnONPs were spherical with an aver...

In this study, we experimentally investigated the nonlinear optical properties of Au nano-particles (Au NPs) that were prepared in pure distilled water using the laser ablation method. The Au NPs were prepared using a nanosecond Nd:YAG laser with an ablation time of 5 or 10 min at a constant laser energy of 100 mJ. The structure and the linear opti...

The nonlinear optical properties of pure ZnO and Ni-doped ZnO thin films are explored using the Z-scan technique at different input laser intensities and an excitation wavelength of 750 nm by 100 fs laser pulses. The pure ZnO and Ni-doped ZnO thin films were prepared by radio frequency magnetron sputtering at room temperature. A scanning electron m...

The synthesis of Au-Ag alloy nanoparticles (NPs) by laser beam exposure of a mixture of monometallic nanoparticle colloids is described. The monometallic Ag and Au NPs are first synthesized in water using pulsed laser ablation. Subsequently, the mixture of Ag and Au nanoparticles is irradiated with a nanosecond pulsed laser beam. The kinetics of Au...

This study was performed to characterize surface topography and microhardness of 40 wt pct NiCrBSiC-60 wt pct WC hard coating on TC4 titanium after coaxial laser cladding via Laser Induced Breakdown Spectroscopy (LIBS) and machine learning. The high content of the hard WC particles is accomplished to enhance the abrasion wear resistance of such all...

This paper introduces modelling and simulation of signal distortions as well as intensity noise induced by two-tone direct intensity modulation of semiconductor lasers for use in radio-over-fibre (RoF) systems. The study develops a large-signal modulation of semiconductor laser simulations in the regime of high-frequency modulation by counting lase...

In this paper, we present results from the measurements of the optical Kerr nonlinearity of indium tin oxide (ITO) thin films of different thicknesses using the femtosecond (fs) Z-scan technique. ITO thin films were prepared by radio frequency magnetron sputtering on a glass substrate at room temperature. The coated ITO thin films were subsequently...

The nonlinear optical properties of silver nanoparticles (AgNPs) colloids in distilled water, when irradiated with 100 fs laser pulses, were investigated experimentally using the Z-scan technique. At a constant wavelength of 760 nm and different excitation powers, the nonlinear absorption coefficient and nonlinear refractive index were measured. Th...

Albumin is the most abundant serum protein that transports hormones, free fatty acids, bilirubin, various ions, and drugs. The current study investigated the potential application of laser-induced fluorescence (LIF) in clinical analysis of human serum albumin (HSA) as a biomarker of liver and kidney disease. The excitation wavelength and HSA concen...

We present a simulation study on the chirping characteristics of a directly modulated 40 Gbps laser diode and evaluate its performance for use in high-speed optical fiber links. The effects of the linewidth enhancement factor (α) and gain suppression on the laser chirp and the maximum fiber transmission length are investigated. The chirp characteri...

This paper experimentally investigated the linear and third-order optical nonlinearities of a pure CuO thin film deposited on a soda-lime glass substrate. A single-phase film with 62 nm thickness was prepared using the direct current (DC) sputtering deposition process, the film structure was measured using x-ray diffraction (XRD) and a surface prof...

This paper experimentally investigated the linear and third-order optical nonlinearities of a pure CuO thin film deposited on a soda-lime glass substrate. A single-phase film with 62 nm thickness was prepared using the direct current (DC) sputtering deposition process, the film structure was measured using x-ray diffraction (XRD) and a surface prof...

Using the Z- scan method, we studied the nonlinear absorption coefficient of rhodamine 6G dissolved in water. With laser pulses of 100 fs, the nonlinear absorption coefficient was measured at different excitation wavelengths and incident powers for both water and R6G. Water behavior showed saturable absorption (SA) at high power (> 0.8 W) but at lo...

Laser ablation in liquids (LAL) is being used to create contaminant-free colloidal nanoparticles with unique properties. The absorbance of a substance to incident laser light, which results in the formation of a nanoparticle, as well as the control of size and shape, are all affected by many factors. Among these are laser energy, laser wavelength,...

Silver nanoparticles are well-known for their antimicrobial effect. However, they are potentially toxic in high doses. We explored the possibility of enhancing the bactericidal effect of low concentrations of silver nanoparticles with blue light femtosecond laser irradiation, since such concentrations are less toxic. The growth dynamics of Pseudomo...

Bismuthene, an unique kind of two-dimensional material beyond graphene, has attracted considerable attention recently for its unique electronic and photonic properties. These unique properties render of Bismuthene as an excellent candidate for various applications, e.g., nonlinear photonics such as optical limiters, optical switchers and all-optica...

We investigated the effect of femtosecond laser irradiation on the growth kinetics of Staphylococcus aureus. In order to improve laser-based antimicrobial therapy and develop a clinically viable modality, various laser parameters such as laser light wavelength, laser power, exposure time, and energy density were studied. The INSPIRE HF100 laser sys...

In the present study, we investigated a numerical simulation for employing fused silica for self-compression of femtosecond laser pulses. Self-compression, resulting from the interaction between self-phase modulation and negative group velocity dispersion, can be solved numerically by the nonlinear Schrodinger equation. Once a laser pulse of 200 fs...

We investigated the influence of femtosecond laser irradiation on the growth of the two most common infectious bacterial pathogens in wounds; Staphylococcus aureus and Pseudomonas aeruginosa as an attempt to validate optimum parameters for a laser-based bactericidal modality to be used clinically. Bacterial cultures were exposed to femtosecond lase...

We have investigated the nonlinear optical properties of indium tin oxide (ITO) thin film coated on soda–lime glass substrate using the z-scan technique. With 100 fs laser pulses, the nonlinear absorption coefficient and nonlinear refractive index are measured at different excitation wavelengths and at different incident intensities. The nonlinear...

We report on using Polymethyl Methacrylate (PMMA) polymer as a broadening material for high-intensity femtosecond laser pulses. The broadened pulse is recompressed using compressor such as pair of gratings or chirped mirrors in order to achieve simplified thin-film compressor with compression factor of 11. The Nonlinear Schrödinger Equation (NLSE)...

In this paper the nonlinear optical properties of Co-doped ZnO and pure ZnO thin films were measured. The films were irradiated with 100 femtosecond laser pulses at 950 nm and at different input intensities ranging from 9 to ${14}\;{{\rm GW/cm}^2}$ . We observed that two-photon absorption induced a reverse saturable absorption and saturable absorpt...

In this paper the nonlinear optical properties of Co-doped ZnO and pure ZnO thin films were measured. The films were irradiated with 100 femtosecond laser pulses at 950 nm and at different input intensities ranging from 9 to 14 GW/cm 2. We observed that two-photon absorption induced a reverse saturable absorption and saturable absorption in Co-dope...

In this study, the optimization of the operating parameters of nonlinear polymers for self-phase modulation is reported. The effect of delocalization length and adding function groups (donor-acceptor groups) on the nonlinear refractive index are investigated. Based on nonlinear Schrödinger equation, the pulse chirping factor, for a set of nonlinear...

In this work, new composites in the form of paste of high density polyethylene (HDPE), commercial borax (BX), sand and Portland cement were designed with different concentrations of each, constructed and tested for 241Am- Be neutrons and 60Co gamma rays. The design depended on the calculated values of the effective removal cross section (ΣR), total...

In this report, we propose a new method for measuring the nonlinear refractive index in liquid and glass samples using femtosecond (fs)-laser pulses with high pulse repetition rates. This method is based on solving the heat equation to derive an expression for the normalized transmittance of closed-aperture Z-scan measurements as a function of the...

lab 2 of practical Laboratory of Tissue Culturing in our Institute Laser Institute for Research and Applications (LIRA). Biological Laser Applications Department.

lab 3 of practical Laboratory of Tissue Culturing in our Institute Laser Institute for Research and Applications (LIRA). Biological Laser Applications Department.

Nonlinear optical properties of soda-lime glasses irradiated by 100 fs laser pulses with intensities ranging from 80 to 182 GW/cm2 and wavelengths from 780 to 870 nm were investigated by the Z-scan technique. Saturated three photon absorption (3PA) was observed and the dependence of the 3PA coefficient on the intensity and the irradiation wavelengt...

practical Laboratory of Tissue Culturing in our Institute Laser Institute for Research and Applications (LIRA). Biological Laser Applications Department.

In this work, fast neutron and gamma ray shield attenuation parameters have been calculated for new composite paste shielding with seven different concentrations of high-density polyethylene (HDPE) and borax (BX) that are mixed with cement and sand. Computer program WinXCom has been used to calculate the total mass attenuation coefficients (µ/) for...

This study aimed to evaluate the effect of quercetin and the photo-stimulatory effect of low energy 632.8 nm laser irradiation on excisional wound healing in non-diabetic and diabetic rats. Streptozotocin (45 mg/kg body weight) was intraperitoneally applied for diabetes induction. A full-thickness skin wound (2 × 2 cm 2) was aseptically created wit...

An optical trap for storing femtosecond laser pulses to enhance the interaction effectiveness with optically thin targets is being proposed and investigated. Presently, we studied the trapping of 10–200 fs laser pulses of wavelength 800 nm, 1 μJ energy per pulse, and 10 Hz repetition rate. To compensate the optical losses in the trap, a Ti: Sapphir...

Abstract: Background: Low level laser therapy (LLLT), commonly known as photo-stimulation or phototherapy has emerged. Methods: One hundred rats were used and streptozotocin (45mg /kg body weight) was applied for diabetic induction. An 2cm2 full thickness skin wound was created a specifically with a scalped in 10 groups of non-diabetic rats and dia...

We focused an intense attosecond pulse train into a neon gas target and observed Ne2+ resulting from two-photon double ionization. By modifying the photon spectrum we find that the process is dominated by the sequential ionization via the Ne+ ion.

We present a demonstration of two-photon double ionization of neon using an intense extreme ultraviolet (XUV) attosecond pulse train (APT) in a photon energy regime where both direct and sequential mechanisms are allowed. For an APT generated through high-order harmonic generation (HHG) in argon we achieve a total pulse energy close to 1μJ, a centr...

We present the first demonstration of two-photon double ionization of neon using an intense extreme ultraviolet (XUV) attosecond pulse train (APT) in a photon energy regime where both direct and sequential mechanisms are allowed. For an APT generated through high-order harmonic generation (HHG) in argon we achieve a total pulse energy close to 1 $\...

We report on the development of an optical setup based on a multipass optical cell and on Mid-IR frequency comb laser for breath analysis. The relevant spectrum covers many biomarkers described in [2]. Perilminary sensitivity estimation for Acetone, Ethane, and Pentane showed that we could reach about 500 ppbv, 10 ppbv, and 75 ppb respectively.

An optical trap for storing femtosecond laser pulses was investigated (fig.1). To compensate the optical losses we intend to use Ti:Sapphire as an amplifying medium. The average power increased by a factor of 100 times.This will be benefit in applications such as medical applications, and laser induced spectroscopy.

We developed a mid-infrared dual frequency comb spectrometer with a mulitpass cell of ~580 m effective length for acetone detection. The detection limit is ~ 2 ppmv under ambient air condition with 80 ms acquisition time.