Prof.Dr.Mithaq Mutter Mehdy Al-sultani

Abstract The linear optical features such as (transmittance T, absorbance A, the effective length

ABSTRACT: The two different dental fillings as composite and amalgam, doped with SiO2 nanoparticles, had been prepared. The optical properties as absorbance , absorption coefficient , transmittance , refractive index , reflectance , extinction coefficient and optical density , had been studied for both of composite and amalgam dental filling at different values of SiO2 nanoparticles weight. The effects for both diode laser power and laser exposure time in the optical properties for composite and amalgam dental filling had been studied. It can be concluded that the silica nanoparticles consolidate the optical properties for dental fillings, while increasing the laser power and laser exposure time induces more optical properties. This behavior can be attributed to the highest absorbing elements in filling with nanoparticles, and the vast increase of molecules excitation had been occurred within dental filling treatment by laser. The main conclusion is that the composite dental filling has more optical properties than amalgam dental filling as the many minerals which exist in composite and increase the absorption process as well as all the adjacent optical processes.

Abstract Three different ethanol solutions of laser dyes as ( cryptocyanine ,Oxazine 4 as well as Cresyl violet ) had been prepared at (5x10-4 M) , and study the linear optical parameters as (maximum absorption wavelength, absorbance , transmittance , absorption coefficient and refractive index for three different solutions . Tm: YLF laser at 1907.8 nm , had been used to study the parameters of Third Harmonic generation in these solutions by using two cells from the same solution depending on the third harmonic power generated from them . Ordinary Refractive index , 3rd harmonic refractive index , the difference between and , 3rd harmonic absorption coefficient , 3rd harmonic electrical conductivity , 3rd harmonic extinction coefficient and the phase shift , gradient of 3rd harmonic electric field , and conversion efficiency , 3rd optical conductivity , The coherence length , The optical density , had been studied for these solutions at different Tm: YLF laser power in one time and at different laser incident angle on the solution cell in another time. It can be concluded that the Oxazine 4 laser dye is the best studied laser dye in 3rd harmonic generation efficiency; while the Cresyl Violet laser dye gives highest 3rd harmonic properties than other studied laser dyes. The main conclusion is that the incident laser power on the liquid laser dyes has the strongest effects in all the 3rd harmonic properties.

Abstract In this paper, thin films were made of 10-4 mol/l of Coumarin 4 laser dye dissolved in ethanol, 0.3 g of PVP polymer and 0.04 g of Al2O3 nanoparticles. The electrical properties such as dielectric constant, phase velocity of laser photons inside the film, the film permittivity and permeability, medium impedance, electrical conductivity, skin depth, the electrical response time, magnetic susceptibility and dielectric time have been studied for the prepared thin films at two different Er:YAG laser wavelengths of 1645nm and 1617 nm based on various laser powers in one time and with changed laser exposure periods in the other time. It is observed that the highest laser power consolidates each value of dielectric constant, dielectric time, electrical conductivity, the electrical response time, magnetic susceptibility and the permeability of film because of increasing the abundant energy in films within laser irradiation. The most important conclusion is that the electrical properties were much higher for the prepared thin films irradiated with 1645nm Er: YAG laser wavelength than for those irradiated with 1617nm laser wavelength.

Four different mixtures of ( 10-3 mol/l Styryl 9M laser dye , 0.1 gm PMMA and one of TiO2 microparticles , Ag and ZnO nanoparticles weights ( 0.02 gm ,0.04 gm , 0.06 gm and 0.08 gm ) ) had been prepared using chloroform solvent .Four different thin films had been made from these mixtures for each particles type using drop casting method .The absorption spectrums of these thin films had been taken . The absorption spectral properties as ( peak wavelength , peak absorbance and frequency difference at half absorbance maximum) had been measured depending on the absorption spectrums for thin films . The non- linear optical properties as (Transmittance difference 〖∆T〗_(p-v)) , Non –linear phase shift 〖∆Φ〗_o , Non-linear Refractive index〖 n〗_2 , Minimum normalized transmittance T(Z) and Non-linear absorption coefficient β) were calculated according to normalized transmittance data obtained from Z—scan setup with closed and open aperture . The effect of the particle size of the scattering centers in the linear and nonlinear optical properties of the Styryl 9M laser doped in PMMA thin films had been studied . The main conclusion is that the Ag nanoparticles causes a shift of the absorption wavelengths to longer wavelengths ( red shift ) , so this helps in choosing the medium and nanoparticles with appropriate excitation wavelengths .

The molecular structure of the Styryl 9M laser dye had been described . Four different concentrations of this dye had been prepared using chloroform solvent .The absorption and fluorescence spectrums of the Styryl 9M laser dye solutions had been taken . The absorption spectral properties as ( peak wavelength , peak absorbance and frequency difference at half absorbance maximum) and the fluorescence spectral properties as ( peak fluorescence intensity , peak wavelength , full width at half maximum , line width and Stock's shift ) had been measured for the prepared solutions . It had been concluded that the dye concentration increasing causes an increasing in the fluorescence photons emitted . The main conclusion is that the highest absorption leads to the fluorescence improvement .

The first Laser Physics Lectures for fourth stage students in new studying year 2021-2022 is 13/10/2021.