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Laser stimulated elasto-optical effects in the proustite crystals (Ag 3 AsS 3 ) under influence of coherent bicolor laser treatment with simultaneous illumination by low power He-Ne laser beams have been discovered for the first time. The changes of the piezo-optics have been explored during the first 3 – 5 min. of illumination by two bicolor coherent nanosecond laser beams at 1064 nm and 532 nm. The changes of the piezo-optical coefficients for the bicolor behaviors of the piezo-optical coefficients versus the photoinduced beam diameters and power densities are explored. Three different laser wavelengths (633 nm, 1064 nm, 3390 nm) have been applied for the probing of the photoinduced changes. The space profiles of the probing beams demonstrate an existence of the quasi-periodic gratings structure. It is shown that the probing beams play an effective role in the observed laser stimulated effects. The principal role here is played by Ag ions participating in the ionic conductivity which favor an internal dc-electric field and related photorefraction.

A principal possibility of formation the nanostructures on the surfaces of 50РЬО-25Вi 2 O з −20Са 2 O з − 5BaO (doped by Eu3+, Er3+, Dy3+) is demonstrated by using multi-coherent beams. As a sources of the photoinducing coherent light we have used nanosecond Nd:YAG and Er:Yb lasers generating at 1064 nm and 1540 nm, respectively. The morphology of the photoinduced surfaces is sensitive to the type of rare earth ions. The thickness of the layer was about 20‖30 nm. Possible mechanisms are explained by coherent photoinduction of the valence electrons.

Recently, the memristor based relaxation oscillators become an important topic in circuit theory where the reactive elements are replaced by memristor which occupies a very small area. In this paper, a design of memristor-based relaxation oscillator is introduced based on exponential memristor model. Unlike previously published oscillators which were built based on a simple memristor model, the exponential model is used, as a generalized model, to verify the concept of memristor based RM oscillator using a model that has electrical characteristic very close to the fabricated device. First, the effect of changing parameters of the memristor is illustrated using graphical analysis. Then, a reasonable range of values for the device parameters are selected to be suitable for the operation of the RM oscillator. The mathematical modeling of the memristor in the oscillator is introduced, in addition to the effect of changing the control voltage on the oscillation frequency. The design and simulations were carried out using Cadence Virtuoso.

A mixture of CdS and CdCl 2 powders with different CdCl 2 weight percentage was used to prepare chlorine doped CdS thin films onto glass substrates using HVE (High Vacuum Evaporation) technique with 1000 A thickness. The influence of chlorine doping on the optical parameters of CdS:Cl films was studied using spectrophotometric measurements of the film transmittance in the wavelength range 200–1100 nm. All the chlorine doped films have sharp fall at the band edge, which is an indication of good crystallinity of the films, and exhibit high optical transmittance (70ߝ90 %) in the range of wavelengths above the absorption edge. It was found that as the CdCl 2 concentration increased the optical energy gap also increased while the refractive index decreased up to 0.10 concentration then stabilized for 0.15 and 0.20 concentrations. It is observed that as the CdCl 2 concentration is increased, the resistivity of the films decreased. The carrier concentration increases with the increase in CdCl 2 concentration which indicates that the chlorine impurity atoms serve as strong donor impurities. A rapid incremental behavior of mobility can be seen with increasing CdCl 2 concentration. This behavior begins to slow down as the doping concentration increases. AFM studies reveal the growth of nano crystalline film structure for pure CdS film as well as the film doped with 0.05 wt% CdCl 2 concentration. These significant results certainly encourage tailoring the CdS films with chlorine doping suitable as window materials required for heterojunction solar cells.

The influence of atomic hydrogen in chemical annealing of a-Si:H films on its optical parameters was studied using spectrophotometric measurements of the film transmittance and reflectance in the wavelength range 200 – 3000 nm. In this chemical annealing, the deposition of a thin layer and treatment with atomic hydrogen were repeated alternately, where both the thickness of the thin cyclic layer, d cyc , and the treatment time for each cycle, t ca , were kept fixed for each sample. A series of different samples with average thickness of 0.5 μm were prepared with different d cyc and t ca . It was found that the refractive index, n, and the optical energy gap, E g , increase as the treatment time,t ca , increases from 0 to 60 seconds, while at t ca = 90 second both n & E g decrease. Also, both the refractive index and the optical energy gap decrease with increasing the relative diffusion length of hydrogen, √t ca /d cyc from 0.39 to 0.77. The widening of E g is due to the structural relaxation resulting from impingement of atomic hydrogen on the growing surface. So, a good quality a-Si:H with the optical energy gap of 1.78 eV exhibiting high stability against light soaking was successfully prepared.