Alaa Yassin Al-Ahmad

Physical origin of observed nonlinearities in Poly (1-naphthyl methacrylate): Using a single transistor?transistor logic modulated laser beam

A thermal lens technique is adopted using a single modulated continuous wave (cw) 532-nm laser beam to evaluate the nonlinear refractive index n2, and the thermo-optic coefficient dn/dT, in polymer Poly (1-naphthyl methacrylate) (P-1-NM) dissolved in chloroform, tetrahydrofuran (THF), and dimethyl sulfoxide (DMSO) solvents. The results are compared with Z-scan and diffraction ring techniques. The comparison reveals the effectiveness and the simplicity of the TTL modulation technique. The physical origin is discussed for the obtained results.

Preparation and study of microstructures, optical properties and oscillator parameters of titanium (IV) oxide (TiO2) film

In this study, Titanium (IV) Oxide (TiO2) film has been prepared and characterized by X-ray diffraction (XRD). The XRD pattern of TiO2 film of anatase phase exhibit very sharp peaks at 25° and 47.85°. According to Scherrer’s formula the grain size of anatase (101) phase TiO2 nananoparticle is 38.5 nm. The optical properties and constants of TiO2 film of thickness (4 μm) have been investigated at room temperature. The transmittance, reflectance and absorbance spectra are measured in the wavelength range (340–900 nm). Optical constants of TiO2 film are derived from the transmission spectra and the refractive index dispersion of the film. The oscillator energy, E0 dispersion energy, Ed, the static refractive index, n0, and other parameters have been determined by the single oscillator Wemple-DiDomenico method. This film can be used in the form of thin film in dye-sensitized solar cells.

Diffused transmission of laser beam and image processing tools for alpha-particle track-etch dosimetry in PM-355 SSNTDs

The present study introduces an optical as well as image processing method that is effective in the study of PM-355 solid state nuclear track detector (SSNTDs) irradiated with α-particles at different times. Laser light with Gaussian extent and 635 nm wavelength is used to accomplish this goal. An imaging processing technique is utilized for the study of the nature and characteristics of a transmitted laser beam through PM-355 SSNTDs. Semi-empirical formulas are obtained which can be used as guide lines to calculate unknown dose. The present method is effective and simple and demands no sophisticated tool methods.