In this work, the external switching dynamics of a Fabry-Perot etalon are studied via optical bistability system simulation. The simulated set-up of this investigation consists of two laser beams; the first beam is continuous (CW) which is considered as a biasing beam and capable of holding the bistable system for a certain range, which we are interested in, from a point that is very close self-switching to a point where the switching is unachievable. The second beam is modulated by passing the first beam through an acousto-optic modulator (AOM) to produce pulses with a minimum rise time and is used as an external source (coherent switching). In this work, we obtained the optical bistable loops by applying absorption coefficient (α) =

 In this research, we studied the effect of (β-rays) on the optical properties of pure  (PMMA) films prepared by using casting technique, and the optical properties for these  films was studied before and after irradiation  by recording the Absorption and Transmission spectra  for a range of wavelength range (190-1100) nm. and then the absorption and Transmission and the reflectivity, extinction coefficient, refractive index, and real and imaginary parts of dielectric constant was studied

the films of cdse pure and doped with copper ratio glass substrate effect od cucomcentration technique thikness doped with copper is an anonmg and the density of state increases

This paper concerns the peristaltic flow of a Williamson fluid with variable viscosity model through porous medium under combined effects of MHD and wall properties. The assumptions of Reynolds number and long wavelength is investigated. The flow is investigated in a wave frame of reference moving with velocity of the wave. The perturbation series in terms of the Weissenberg number (We <1) was used to obtain explicit forms for velocity field and stream function. The effects of thermal conductivity, Grashof number, Darcy number, magnet, rigidity, stiffness of the wall and viscous damping force parameters on velocity and stream function have been studied.

AgInSe2 (AIS) thin films solar cell involving of n-type AgInSe2 and Si of p-type substrate by using thermal evaporation method. The influence of annealing of the preparation AgInSe2 were considered to find the best properties of solar device. Thin film AIS have been deposited under the vacuum of 1.5*10-6 Torr with (400) nm thickness at R.T and annealing temperatures (473,573) K. Polycrystalline tetragonal structure for AIS thin films from XRD and increasing of surface roughness from AFM, energy gap values decreasing with increasing annealing temperatures, all films were negative type, I-V characteristics show increasing of efficiency with increasing of annealing temperatures.

In this work, an investigation for the dynamic analysis of thin composite cylindrical and spherical shells is presented. The analytical solution is based upon the higher order shear deformation theory of elastic shells from which the developed equations are derived to deal with orthotropic layers. This will cover the determination of the fundamental natural frequencies and mode shapes for simply supported composites cylindrical and spherical shells.

      The analytical results obtained by using the derived equations were confirmed by the finite element technique using the well known Ansys package. The results have shown a good agreement with a maximum percentage of discrepancy, which gives a confidence o

The study of surface hardness, wear resistance, adhesion strength, electrochemical corrosion resistance and thermal conductivity of coatings composed from sodium silicate was prepared using graphite micro-size particles and carbon nano particles as fillers respectively of concentration of (1-5%), for the purpose of covering and protecting the oil distillation towers. The results showed that the sodium silicate coating reinforced with carbon nano-powder has higher resistance to stitches, mechanical wear, adhesive and thermal conductivity than graphite/sodium silicate composite especially when the ratio 5% and 1%, the electrochemical corrosion test confirmed that the coating process of stainless steel 304 lead to increasin

Ytterbium-doped (Y2O3), (Sc2O3) and (YAG) crystals are very important for high-power thindisk lasers. These lasers have shown their ability to operate quasi-three-level materials with high
efficiency as well as high thermal conductivity ratio for crystalline hosts. All these reasons have
required studying this type of laser. In the present work, the analytical solution was found for the
equation of laser output power, pumping threshold power, and efficiency of a quasi-three-level
thin disk laser. The numerical solution of these equations was also found through the Matlab
program at the fundamental transverse mode, at a temperature of 299K0
and with high pumping
capabilities in order to know the e

      In this work, the performance of single-mode optical fibers (SMFs) for ultraviolet (UV) radiation monitoring and dosimetry applications is presented. In particular, this work will focus on the Radiation-Induced Absorption (RIA) phenomena in the Near-Infrared domain (NIR). Such phenomena play a very important role in the sensing mechanism for SMF. Single mode fibers with a diameter of 50 µm were used for this purpose. These fibers were dipped into germanium (Ge) solution with different concentrations (1, 3, and 5 wt%) to produce the sensing part of the sensor. For all optical fiber sensors under investigation, the results indicated the dependence of the RIA on the applied UV radiation energy. Also, a redshi

     In this paper, we experimentally studied the effects of optical power of semiconductor laser on the electrical properties of silicon diode of an exposed device. The experimental results showed that the laser diode light of different optical powers (2, 3, and 4 mW) had effects on the silicon diode that are somewhat similar to those of thermal treatment. A shift in the current-voltage curve to the left side was also noticed, which led to a non-linear decrease of the barrier voltage of the diode by the effect of laser light. We also reveal a decrease by 344.8 nA/mW in the reverse saturation current of the silicon diode as a result of exposure to laser light. The forward resistance of the silicon diode decreased with