Tessema, Genene (PhD)Hailu, Girma2018-06-262023-11-092018-06-262023-11-092007-03http://10.90.10.223:4000/handle/123456789/3647With the development of strong laser sources for different applications which in some instances has extremely high intensity, optical power limiters are needed to provide human eye and optical detector protection. So, a smart ultra fast optical power limiter that is transparent for low incident intensities and blocks the output at high input intensities is required. The operation of optical power limiters is based on the phenomena of nonlinear absorption (NLA). Different Porphyrins have been reported to have NLA property which put them as potential candidate for application as optical power limiters. In this paper, we have investigated NLA and optical limiting properties of five different types of Porphyrins by using the Z-scanning technique. The Porphyrins were confined into Nafion membrane in order to protect them from possible degradation. The results of the experiments clearly show the fascinating NLA and optical power limiting properties of the Porphyrins under investigation. By fitting the Z-scan results with the theoretical fitting function, the nonlinear absorption coefficients (¯) of all the Porphyrins with different concentrations for each of them is determined. Besides, their linear absorption coefficients are obtained by considering low intensity regimes from the data and applying Beer’s low of linear absorptionenThe Study of Porphyrins ConfinementThesis