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Now single crystalline fibers became the subject of increasing interest, because of their remarkable characteristics. Due to large length-to-diameter ratio composed with perfect crystal structure and chemical homogeneity, the mechanical and physical properties approach theoretical values. In this work we are interested in grown of single crystal fibers for Laser, optics, non linear optics and Scintillation applications. Beside that, we are trying during this work to develop a new material that have specific thermo-mechanical properties (in particular low loss angle) to be used as a suspension for the mirror in advanced gravitation waves detector in order to decrease the low thermal noise. For these applications, it is important that fibers be produced in specifc length,diameters and orientations. Throughout the chapters I will show the growth process, the main problems encountered during the growth of these materials and the potentialities of the method. For the different rare ear doped hosts I will show the structural & spectroscopic performance like absorption, fluorescence and decay time. Thermo-mechanical properties of grown Si fibers will be shown briefly at room temperature.

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Born in Egypt in October 1974. He has been graduated from Physics departement of Al-Azhar University, Egypt, in 1997. He awarded the B.Sc in physics from the same university in November 2000 and later on he awarded Ph.D. degree in Physics from Pisa University, Italy 2005. He has a long experimental experience in physics and chemistry of materials.

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