تحضير ودراسة الخواص الطيفيه الى الوسط الليزري الفعال Er : TiO باستخدام تقانة الصول - جل == Preparation and Study of the Spectroscopic Properties of Er : TiO2 Laser Active Medium using Sol - Gel Technique
Author name:
هناء محمد ياسين
Supervisor name:
صباح نوري مزهر | بسام غالب رشيد
General topic:
Physics
Specific topic:
Laser Physics and Electro-optics
Degree:
Doctorate
University:
University of Baghdad
Language:
English
University location:
Baghdad
First pages:
26T1979 - p.pdf
Abstract:
ions Doped nano particular titanium dioxide was prepared via sol - gel method under varying conditions (with doping rates equal to 1.24%wt, 2.65%wt, 3.78%wt, 5.05%wt and 6.31%wt). The structure, morphological and spectroscopic properties of prepared doped samples were investigated by a variety of techniques, including XRD, AFM , UV - Visible spectroscopy and photoluminescence spectroscopy.XRD analysis shows that TiO2 prepared samples have amorphous structure turn to polycrystalline anatase structure after annealing process. The lattice constant parameters 'a' and 'c' of the tetragonal lattice anatase TiO2 powder has been calculated; the results showed that the value of 'a' remains essentially unchanged, while the lattice constant 'c' have slightly increased at lower doping rate then become stable at higher doping rate. This is due to a combination of interstitial and substitutional accommodation of the dopant ions.The FTIR spectra for pure and doped samples after annealing process show a single transition peak at wave number around 1200cm - 1 and 1102 cm - 1 respectively. The wavelength of high transition rate of this peak depends on Er3+ concentrations. By Comparing with wavelength of high transition rate of pure TiO2 sample, slightly peak wavelength increments shift occur with increment of doping concentration rate. FTIR spectra give a good indication in direction of synthesis of optical band - pass filter at a wavelength around 9.07μm (~1102 cm - 1).Judd - Ofelt analysis is performed to calculate the three Judd - ofelt of parameters; Ω2, Ω4 and Ω6. From the absorption spectra, the radiative transition probabilities A(J;J’), radiative lifetime τrad and fluorescence branching ratioare calculated for each excited upper manifolds states of Er3+ .A photoluminescence peaks was recorded at wavelength around to 498nm, 533nm and 1533 nm. The emission cross - section σem for prepared samples are calculated. It was founds that sample with doping rate 5.05%wt have high σem values in compares with other samples, and it’s value is close to those value of Er : Glass.According to the spectroscopic properties of doped samples, it could be concluded that Er : TiO2 has the potential to be a laser mat
