Omed Abdullah | University of Sulaimani (original) (raw)
Papers by Omed Abdullah
Your article is protected by copyright and all rights are held exclusively by Springer Science +B... more Your article is protected by copyright and all rights are held exclusively by Springer Science +Business Media New York. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(eth... more Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO), with different concentration of copper (II) chloride (CuCl 2 ) were prepared using casting technique. Optical studies were performed using Fourier transform infrared (FT-IR) and Ultraviolet-visible (UV-Vis) spectroscopy. The optical properties of these films were varied by varying CuCl 2 concentration. The results show the absorption edge for electrolyte samples shifts toward a lower energy region by increasing the salt concentration, leading to the band gap reduction. The band gap energy data showed that the incorporation of CuCl 2 into the polymeric system causes charge transfer complexes in the blend polymer, which lead to increase in the electrical conductivity, by providing additional charges in the lattice. The PVA/PEO/CuCl 2 solid polymer electrolyte films exhibit good UV shielding properties in the wavelength range from 190 to 400 nm.
ABSTRACT Electrolyte composite films of Polyvinyl alcohol (PVA)0.9 filled with potassium hydrogen... more ABSTRACT Electrolyte composite films of Polyvinyl alcohol (PVA)0.9 filled with potassium hydrogen sulfate (KHSO4)0.1 with different concentration of sodium iodide (NaI) were prepared using solution caste technique. The absorption spectral analysis data were carred for the samples to determine the influence of NaI contents, the obtained data showed that the direct allowed optical energy gap of the films decreases from 6.316 eV to 4.964 eV with increasing NaI contents up to 20% weight. Furthermore, in order to understand the behavior of electrical conduction in these composite, the alternating electrical conductivity and dielectric permittivity have been investigated for different concentration of NaI at temperature range (300-350)K over the frequency ranging from 10KHz to 1MHz. The electrical conductivity of the composite increased with increasing temperature and it obeys power law Aω^s in which s is in the range of 0.3<s<0.7.
Journal of Materials Science: Materials in Electronics, 2016
European Scientific Journal, 2014
Solid polymer electrolyte films based on polyvinyl alcohol complexed with Barium nitrate salt at ... more Solid polymer electrolyte films based on polyvinyl alcohol complexed with Barium nitrate salt at different weight percent were prepared using solution cast technique. The optical absorption coefficient was used to study the nature of electronic transitions between the valence and conduction bands. From the derivation of Tauc's relation it was found that the optical absorption is due to directand indirect allowed transitions. The reduction of energy band gap and increase of tail localized states was observed with increasing Barium nitrate content. The values of refractive index, extinction coefficient, the optical complex dielectric constant have been also calculated. The higher refractive index of solid polymer electrolytes was attributed to the higher molecular packing density compared to that of pure polymer. The increase of optical dielectric constant with increasing salt concentration indicates the presence of a higher density of states and increase in the amount of charge carrier concentration within the polymer electrolyte films.
Universal Journal of Materials Science, 2015
Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(eth... more Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO), with different concentration of copper (II) chloride (CuCl 2 ) were prepared using casting technique. Optical studies were performed using Fourier transform infrared (FT-IR) and Ultraviolet-visible (UV-Vis) spectroscopy. The optical properties of these films were varied by varying CuCl 2 concentration. The results show the absorption edge for electrolyte samples shifts toward a lower energy region by increasing the salt concentration, leading to the band gap reduction. The band gap energy data showed that the incorporation of CuCl 2 into the polymeric system causes charge transfer complexes in the blend polymer, which lead to increase in the electrical conductivity, by providing additional charges in the lattice. The PVA/PEO/CuCl 2 solid polymer electrolyte films exhibit good UV shielding properties in the wavelength range from 190 to 400 nm.
The mechanical behaviour of alumina ceramic powder during compaction, unloading and ejection are ... more The mechanical behaviour of alumina ceramic powder during compaction, unloading and ejection are analyzed using Finite Element Methods (FEM), in which the powder is modeled as an elastic-plastic continuum material. The modify Drucker-Prager Cap (DPC) model was chosen as the yield surface of the medium. The elastic properties and plastic parameters of the model were expressed as a function of density, from which realistic powder properties are generated and fed into ABAQUS finite element code; and the constitutive modeling of the frictional behaviour of the powder in the die is modeled by Coulomb's friction low. Good agreement between the experimental and FEM results are observed, which demonstrates that FEM can capture the major features of the powder behaviour during compaction.
The UV/VIS optical absorption for difference compositions copper oxide doped polystyrene thin fil... more The UV/VIS optical absorption for difference compositions copper oxide doped polystyrene thin films were studied in the wavelength 200-1000 nm. It was found that the optical absorption is due to direct allowed transitions, and the energy gaps shows nonlinear behavior with copper oxide concentration, optical energy gap showed a decreasing trend with increased dopant concentration up to 10% of the dopant, for further increase in dopant concentration this value started increasing again due to segregation effects. The annealing of the samples at temperature 90 ܥ for ݏݎ݄4 , caused the decrease in energy gaps. The studies of the real ߳ and imaginary ߳ parts of the dielectric constants showed that they are also affected by copper oxide concentration.
Iosr Journal of Applied Physics, 2013
Polymer electrolytes based on Polyvinyl alcohol -Cadmium Chloride were prepared by solution cast ... more Polymer electrolytes based on Polyvinyl alcohol -Cadmium Chloride were prepared by solution cast technique. Results of optical absorption, transmission spectra, refractive index, optical band gaps, optical conductance, single oscillator energy, dispersion energy, real and imaginary parts of dielectric constants studies are presented. The optical properties were obtained using UV-VIS Double Beam Spectrophotometer in the wavelength range (190-1100) nm. The optical transmittance at wavelength ≈ 190nm for pure PVA was nearly at 78%, while it was 50% for all doped samples. The optical transmittance was increased with increasing wavelength up to 98% for all films beyond ≈240nm. The calculated energy band gap changes from 6.42eV (pure PVA) to 5.80eV (PVA-20%CdCl 2 .H 2 O). The optical conductance and band-gap indicated that the films are almost transmitting within the visible range. The single oscillator expression has been used to obtain the information about disorder degree. The real and imaginary parts of dielectric constant of the doped films increases with increasing CdCl 2 .H 2 O concentration, and it shows decreases abruptly in the wavelength (200-220) nm, and finally becomes constant with increase in photon energy.
ABSTRACT In this work an attempt has been made to study the various dielectric parameters of poly... more ABSTRACT In this work an attempt has been made to study the various dielectric parameters of polystyrene film. The dielectric constant ' , dielectric loss " and loss tangent tan have been determined in the frequency range (11000)KHz at different temperatures. The frequency dependent conductivity ac was also measured to characterize the polymer. The complex impedance plot (cole-cole plot) was used to calculate the static dielectric constant s , infinitely large frequency dielectric constant and relaxation times. Finally the results are analyzed in terms of different parameters.
ABSTRACT Optical properties of prepared Polystyrene (PS) films with different filling levels of Z... more ABSTRACT Optical properties of prepared Polystyrene (PS) films with different filling levels of Zirconia have been investigated in the visible and ultraviolent wavelength regions. It was found that the optical absorption is due to direct-allowed transitions, and the energy gaps decrease with increasing Zirconia content for all transitions, while the width of the tail localized states increase with increasing Zirconia content. The band gap of all films shows to be decrease after thermal treatment. The optical constants refractive index n, extinction coefficient k, have been also calculated. The refractive index increased in the composite samples as compared with the pure PS sample prepared by the same method.
Advances in Physics Theories and Applications, 2014
In this study, the part in question of the total energy is that due to the mutual interactions be... more In this study, the part in question of the total energy is that due to the mutual interactions between the electrons themselves, the fact that this is the total effective energy of sample electrons in shells and sub-shells. The result was that only 0.2564 of the total energy of the atom is divided between the individual electrons and the effective energy of each of them is proportional to the reciprocal of their occupation numbers i.e. 1/(n+2l+1) 2 , the proportionality constant was fortunately equivalent to the effective nuclear charge (Z eff ) of the sub-shell type according to the studies done by both Slater and Clementi and Raimondi. The amazing news was that the algebraic sum of the effective energy for each electron was again very close to 0.2564 E T .
Journal of Materials Science: Materials in Electronics, 2015
Universal Journal of Materials Science, 2015
Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(eth... more Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO), with different concentration of copper (II) chloride (CuCl 2 ) were prepared using casting technique. Optical studies were performed using Fourier transform infrared (FT-IR) and Ultraviolet-visible (UV-Vis) spectroscopy. The optical properties of these films were varied by varying CuCl 2 concentration. The results show the absorption edge for electrolyte samples shifts toward a lower energy region by increasing the salt concentration, leading to the band gap reduction. The band gap energy data showed that the incorporation of CuCl 2 into the polymeric system causes charge transfer complexes in the blend polymer, which lead to increase in the electrical conductivity, by providing additional charges in the lattice. The PVA/PEO/CuCl 2 solid polymer electrolyte films exhibit good UV shielding properties in the wavelength range from 190 to 400 nm.
Optical properties of solid polymer electrolyte films based on polyvinyl alcohol (PVA) with diffe... more Optical properties of solid polymer electrolyte films based on polyvinyl alcohol (PVA) with different concentration of cobalt nitrate Co(NO3)2 (3-12) wt% have been studied. The parameters such as refractive index, extinction coefficient, and optical energy gap were investigated by using the absorbance measurement from UV-visible spectrophotometer in the spectral range (190-790) nm. This study reveals that the optical properties of PVA are affected by salt concentration, where the absorption increases and absorption edge decreases as Co(NO3)2 concentration increases. The refractive index, and extinction coefficient values were found to increase with increasing Co(NO3)2 percentage. The optical energy gaps have been investigated and showed a clear dependence on the Co(NO3)2 concentration. The interpreted absorption mechanism is both direct- and indirect- electron transition, and it was found to be decreasing with increasing Co(NO3)2 concentration. The single oscillator model has been u...
Journal of Materials Science: Materials in Electronics, 2015
Journal of Materials Science: Materials in Electronics, 2015
IOSR Journal of Applied Physics, 2013
Polymer electrolytes based on Polyvinyl alcohol -Cadmium Chloride were prepared by solution cast ... more Polymer electrolytes based on Polyvinyl alcohol -Cadmium Chloride were prepared by solution cast technique. Results of optical absorption, transmission spectra, refractive index, optical band gaps, optical conductance, single oscillator energy, dispersion energy, real and imaginary parts of dielectric constants studies are presented. The optical properties were obtained using UV-VIS Double Beam Spectrophotometer in the wavelength range (190-1100) nm. The optical transmittance at wavelength ≈ 190nm for pure PVA was nearly at 78%, while it was 50% for all doped samples. The optical transmittance was increased with increasing wavelength up to 98% for all films beyond ≈240nm. The calculated energy band gap changes from 6.42eV (pure PVA) to 5.80eV (PVA-20%CdCl 2 .H 2 O). The optical conductance and band-gap indicated that the films are almost transmitting within the visible range. The single oscillator expression has been used to obtain the information about disorder degree. The real and imaginary parts of dielectric constant of the doped films increases with increasing CdCl 2 .H 2 O concentration, and it shows decreases abruptly in the wavelength (200-220) nm, and finally becomes constant with increase in photon energy.
2010 Second International Conference on Computer Research and Development, 2010
ABSTRACT The passive Q-switched performance of the ruby laser with slow-relaxing solid-state satu... more ABSTRACT The passive Q-switched performance of the ruby laser with slow-relaxing solid-state saturable absorber calcium fluoride crystals doped with divalent dysprosium Dy2+:CaF2 is numerically investigated by solving the coupled rate equations with the Runge-Kutta-Fehlberg method. In the mean time, important factors such as the laser population inversion at various stages, the peak photon number inside the laser resonator, the output energy and the pulse width of the Q-switched laser output are computed. For typical configuration, a Q-switched laser pulse of 150 ns in duration and 3 mJ in energy is obtained. Also the effects of the pumping rate, reflectivity of output coupler, and saturable absorber doping concentration on output laser characteristics are studied. The simulated results show reasonable agreement with those obtained experimentally by other research groups.
Your article is protected by copyright and all rights are held exclusively by Springer Science +B... more Your article is protected by copyright and all rights are held exclusively by Springer Science +Business Media New York. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".
Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(eth... more Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO), with different concentration of copper (II) chloride (CuCl 2 ) were prepared using casting technique. Optical studies were performed using Fourier transform infrared (FT-IR) and Ultraviolet-visible (UV-Vis) spectroscopy. The optical properties of these films were varied by varying CuCl 2 concentration. The results show the absorption edge for electrolyte samples shifts toward a lower energy region by increasing the salt concentration, leading to the band gap reduction. The band gap energy data showed that the incorporation of CuCl 2 into the polymeric system causes charge transfer complexes in the blend polymer, which lead to increase in the electrical conductivity, by providing additional charges in the lattice. The PVA/PEO/CuCl 2 solid polymer electrolyte films exhibit good UV shielding properties in the wavelength range from 190 to 400 nm.
ABSTRACT Electrolyte composite films of Polyvinyl alcohol (PVA)0.9 filled with potassium hydrogen... more ABSTRACT Electrolyte composite films of Polyvinyl alcohol (PVA)0.9 filled with potassium hydrogen sulfate (KHSO4)0.1 with different concentration of sodium iodide (NaI) were prepared using solution caste technique. The absorption spectral analysis data were carred for the samples to determine the influence of NaI contents, the obtained data showed that the direct allowed optical energy gap of the films decreases from 6.316 eV to 4.964 eV with increasing NaI contents up to 20% weight. Furthermore, in order to understand the behavior of electrical conduction in these composite, the alternating electrical conductivity and dielectric permittivity have been investigated for different concentration of NaI at temperature range (300-350)K over the frequency ranging from 10KHz to 1MHz. The electrical conductivity of the composite increased with increasing temperature and it obeys power law Aω^s in which s is in the range of 0.3<s<0.7.
Journal of Materials Science: Materials in Electronics, 2016
European Scientific Journal, 2014
Solid polymer electrolyte films based on polyvinyl alcohol complexed with Barium nitrate salt at ... more Solid polymer electrolyte films based on polyvinyl alcohol complexed with Barium nitrate salt at different weight percent were prepared using solution cast technique. The optical absorption coefficient was used to study the nature of electronic transitions between the valence and conduction bands. From the derivation of Tauc's relation it was found that the optical absorption is due to directand indirect allowed transitions. The reduction of energy band gap and increase of tail localized states was observed with increasing Barium nitrate content. The values of refractive index, extinction coefficient, the optical complex dielectric constant have been also calculated. The higher refractive index of solid polymer electrolytes was attributed to the higher molecular packing density compared to that of pure polymer. The increase of optical dielectric constant with increasing salt concentration indicates the presence of a higher density of states and increase in the amount of charge carrier concentration within the polymer electrolyte films.
Universal Journal of Materials Science, 2015
Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(eth... more Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO), with different concentration of copper (II) chloride (CuCl 2 ) were prepared using casting technique. Optical studies were performed using Fourier transform infrared (FT-IR) and Ultraviolet-visible (UV-Vis) spectroscopy. The optical properties of these films were varied by varying CuCl 2 concentration. The results show the absorption edge for electrolyte samples shifts toward a lower energy region by increasing the salt concentration, leading to the band gap reduction. The band gap energy data showed that the incorporation of CuCl 2 into the polymeric system causes charge transfer complexes in the blend polymer, which lead to increase in the electrical conductivity, by providing additional charges in the lattice. The PVA/PEO/CuCl 2 solid polymer electrolyte films exhibit good UV shielding properties in the wavelength range from 190 to 400 nm.
The mechanical behaviour of alumina ceramic powder during compaction, unloading and ejection are ... more The mechanical behaviour of alumina ceramic powder during compaction, unloading and ejection are analyzed using Finite Element Methods (FEM), in which the powder is modeled as an elastic-plastic continuum material. The modify Drucker-Prager Cap (DPC) model was chosen as the yield surface of the medium. The elastic properties and plastic parameters of the model were expressed as a function of density, from which realistic powder properties are generated and fed into ABAQUS finite element code; and the constitutive modeling of the frictional behaviour of the powder in the die is modeled by Coulomb's friction low. Good agreement between the experimental and FEM results are observed, which demonstrates that FEM can capture the major features of the powder behaviour during compaction.
The UV/VIS optical absorption for difference compositions copper oxide doped polystyrene thin fil... more The UV/VIS optical absorption for difference compositions copper oxide doped polystyrene thin films were studied in the wavelength 200-1000 nm. It was found that the optical absorption is due to direct allowed transitions, and the energy gaps shows nonlinear behavior with copper oxide concentration, optical energy gap showed a decreasing trend with increased dopant concentration up to 10% of the dopant, for further increase in dopant concentration this value started increasing again due to segregation effects. The annealing of the samples at temperature 90 ܥ for ݏݎ݄4 , caused the decrease in energy gaps. The studies of the real ߳ and imaginary ߳ parts of the dielectric constants showed that they are also affected by copper oxide concentration.
Iosr Journal of Applied Physics, 2013
Polymer electrolytes based on Polyvinyl alcohol -Cadmium Chloride were prepared by solution cast ... more Polymer electrolytes based on Polyvinyl alcohol -Cadmium Chloride were prepared by solution cast technique. Results of optical absorption, transmission spectra, refractive index, optical band gaps, optical conductance, single oscillator energy, dispersion energy, real and imaginary parts of dielectric constants studies are presented. The optical properties were obtained using UV-VIS Double Beam Spectrophotometer in the wavelength range (190-1100) nm. The optical transmittance at wavelength ≈ 190nm for pure PVA was nearly at 78%, while it was 50% for all doped samples. The optical transmittance was increased with increasing wavelength up to 98% for all films beyond ≈240nm. The calculated energy band gap changes from 6.42eV (pure PVA) to 5.80eV (PVA-20%CdCl 2 .H 2 O). The optical conductance and band-gap indicated that the films are almost transmitting within the visible range. The single oscillator expression has been used to obtain the information about disorder degree. The real and imaginary parts of dielectric constant of the doped films increases with increasing CdCl 2 .H 2 O concentration, and it shows decreases abruptly in the wavelength (200-220) nm, and finally becomes constant with increase in photon energy.
ABSTRACT In this work an attempt has been made to study the various dielectric parameters of poly... more ABSTRACT In this work an attempt has been made to study the various dielectric parameters of polystyrene film. The dielectric constant ' , dielectric loss " and loss tangent tan have been determined in the frequency range (11000)KHz at different temperatures. The frequency dependent conductivity ac was also measured to characterize the polymer. The complex impedance plot (cole-cole plot) was used to calculate the static dielectric constant s , infinitely large frequency dielectric constant and relaxation times. Finally the results are analyzed in terms of different parameters.
ABSTRACT Optical properties of prepared Polystyrene (PS) films with different filling levels of Z... more ABSTRACT Optical properties of prepared Polystyrene (PS) films with different filling levels of Zirconia have been investigated in the visible and ultraviolent wavelength regions. It was found that the optical absorption is due to direct-allowed transitions, and the energy gaps decrease with increasing Zirconia content for all transitions, while the width of the tail localized states increase with increasing Zirconia content. The band gap of all films shows to be decrease after thermal treatment. The optical constants refractive index n, extinction coefficient k, have been also calculated. The refractive index increased in the composite samples as compared with the pure PS sample prepared by the same method.
Advances in Physics Theories and Applications, 2014
In this study, the part in question of the total energy is that due to the mutual interactions be... more In this study, the part in question of the total energy is that due to the mutual interactions between the electrons themselves, the fact that this is the total effective energy of sample electrons in shells and sub-shells. The result was that only 0.2564 of the total energy of the atom is divided between the individual electrons and the effective energy of each of them is proportional to the reciprocal of their occupation numbers i.e. 1/(n+2l+1) 2 , the proportionality constant was fortunately equivalent to the effective nuclear charge (Z eff ) of the sub-shell type according to the studies done by both Slater and Clementi and Raimondi. The amazing news was that the algebraic sum of the effective energy for each electron was again very close to 0.2564 E T .
Journal of Materials Science: Materials in Electronics, 2015
Universal Journal of Materials Science, 2015
Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(eth... more Solid polymer electrolyte films based on polymer blends of poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO), with different concentration of copper (II) chloride (CuCl 2 ) were prepared using casting technique. Optical studies were performed using Fourier transform infrared (FT-IR) and Ultraviolet-visible (UV-Vis) spectroscopy. The optical properties of these films were varied by varying CuCl 2 concentration. The results show the absorption edge for electrolyte samples shifts toward a lower energy region by increasing the salt concentration, leading to the band gap reduction. The band gap energy data showed that the incorporation of CuCl 2 into the polymeric system causes charge transfer complexes in the blend polymer, which lead to increase in the electrical conductivity, by providing additional charges in the lattice. The PVA/PEO/CuCl 2 solid polymer electrolyte films exhibit good UV shielding properties in the wavelength range from 190 to 400 nm.
Optical properties of solid polymer electrolyte films based on polyvinyl alcohol (PVA) with diffe... more Optical properties of solid polymer electrolyte films based on polyvinyl alcohol (PVA) with different concentration of cobalt nitrate Co(NO3)2 (3-12) wt% have been studied. The parameters such as refractive index, extinction coefficient, and optical energy gap were investigated by using the absorbance measurement from UV-visible spectrophotometer in the spectral range (190-790) nm. This study reveals that the optical properties of PVA are affected by salt concentration, where the absorption increases and absorption edge decreases as Co(NO3)2 concentration increases. The refractive index, and extinction coefficient values were found to increase with increasing Co(NO3)2 percentage. The optical energy gaps have been investigated and showed a clear dependence on the Co(NO3)2 concentration. The interpreted absorption mechanism is both direct- and indirect- electron transition, and it was found to be decreasing with increasing Co(NO3)2 concentration. The single oscillator model has been u...
Journal of Materials Science: Materials in Electronics, 2015
Journal of Materials Science: Materials in Electronics, 2015
IOSR Journal of Applied Physics, 2013
Polymer electrolytes based on Polyvinyl alcohol -Cadmium Chloride were prepared by solution cast ... more Polymer electrolytes based on Polyvinyl alcohol -Cadmium Chloride were prepared by solution cast technique. Results of optical absorption, transmission spectra, refractive index, optical band gaps, optical conductance, single oscillator energy, dispersion energy, real and imaginary parts of dielectric constants studies are presented. The optical properties were obtained using UV-VIS Double Beam Spectrophotometer in the wavelength range (190-1100) nm. The optical transmittance at wavelength ≈ 190nm for pure PVA was nearly at 78%, while it was 50% for all doped samples. The optical transmittance was increased with increasing wavelength up to 98% for all films beyond ≈240nm. The calculated energy band gap changes from 6.42eV (pure PVA) to 5.80eV (PVA-20%CdCl 2 .H 2 O). The optical conductance and band-gap indicated that the films are almost transmitting within the visible range. The single oscillator expression has been used to obtain the information about disorder degree. The real and imaginary parts of dielectric constant of the doped films increases with increasing CdCl 2 .H 2 O concentration, and it shows decreases abruptly in the wavelength (200-220) nm, and finally becomes constant with increase in photon energy.
2010 Second International Conference on Computer Research and Development, 2010
ABSTRACT The passive Q-switched performance of the ruby laser with slow-relaxing solid-state satu... more ABSTRACT The passive Q-switched performance of the ruby laser with slow-relaxing solid-state saturable absorber calcium fluoride crystals doped with divalent dysprosium Dy2+:CaF2 is numerically investigated by solving the coupled rate equations with the Runge-Kutta-Fehlberg method. In the mean time, important factors such as the laser population inversion at various stages, the peak photon number inside the laser resonator, the output energy and the pulse width of the Q-switched laser output are computed. For typical configuration, a Q-switched laser pulse of 150 ns in duration and 3 mJ in energy is obtained. Also the effects of the pumping rate, reflectivity of output coupler, and saturable absorber doping concentration on output laser characteristics are studied. The simulated results show reasonable agreement with those obtained experimentally by other research groups.