No abstract

No abstract

Holmium (Ho 3+)-doped TiO 2 solid laser active materials with different concentrations (1, 3, 5, and 7 wt%) of Ho 3+ ions were prepared using a sol-gel method. A structural study of the samples using X-ray diffraction (XRD) revealed the anatase phase of pure and doped TiO 2 calcined at 500 C, which is confirmed by (101), (004), (200), (105), (211), (204), (116), (220) and (215) diffraction peaks. XRD analysis showen a deformation along the c-axis of the anatase lattice constant with doping, and a random change in the grain size of the doped titania with respect to pure samples. The presence of the titania bonds (Ti-O-Ti) and (Ti-O) of pure and Ho 3+-doped samples were confirmed from the FTIR spectroscopy study of the samples. In addition, it was noted that bands around 1338, and 1339 cm −1 belonging to 3, 5, and 7 wt% dopant concentrations, while no band for 1 wt% was observed. UV-Vis spectrophotometer and spectrofluorophotometer techniques were used to study the optical and spectroscopic characterizations of these samples. It was found that various fluorescence peaks for Ho 3+ ions were observed in the UV-vis region under different pump wavelengths. This is a good indication of suitability of the material to be employed as a laser active medium.

Tin oxide films (SnO2) of thickness (1 ?m) are prepared on glass substrate by post oxidation of metal films technique. Films were irradiated with Nd:YAG double frequency laser of wavelength (532 nm) pulses of three energies (100, 500, 1000) mJ. The optical absorption, transmission, reflectance, refractive index and optical conductivity of these films are investigated in the UV-Vis region (200-900) nm. It was found that the average transmittance of the films is around (80%) at wavelength (550 nm) and showed high transmission (? 90 %) in the visible and near infrared region. The absorption edge shifts towards higher energies, which is due to the Moss-Burstien effect and it lies at (4 eV). The optical band gap increased with increasing of energy.