Characterization of Magnetite and 2-line Ferrihydrite Using Laser Raman Spectroscopy

In this work, laser Raman Spectroscopy was used for the characterization of magnetite and 2-line ferrihydrite. These samples were irradiated using 5mW frequency doubled Nd-YAG laser with 532 nm at room temperature and their Raman spectra were recorded. The spectral database was used for the spectral analysis of the Raman shift of the two samples

Evaluation of a Constructed Optical Coherence Tomography System

The objective of this work is to design and construct an optical coherence tomography (OCT) system, beside the comparison of the efficiency of this system with other tomography systems, like Photoacoustic system, to evaluate its operation. Michelson interferometer was designed; which represent the heart of the system. Two types of laser sources were used; they were He-Ne laser with wavelength of 632.8 nm and semiconductor laser with wavelengths of (700) nm. Performance of the constructed system was completed by receiving the interference fringes by an optical detector, which was connected to the display unit. Digital oscilloscope, with Fourier transformation, was used to display the signal information in frequency domain. Also CCD camera was used to give two & three dimensional images for the studied samples. The constructed system can be used for many purposes, for examples: measurement of the thickness and determination of the optical properties for different samples. The samples studied by the constructed OCT system were: glass slides, polymer\ pyrex\ carbon coating, layers of onion. To prove the good performance of the constructed OCT system the results were compared with other results gained by a Photoacoustic system for the polymer sample. The comparison proved that the constructed OCT system is operated efficiently and correctly