Fabrication of micro holographic optical elements by interference of a single pulse from femtosecond laser

Summary form only given. By fully utilizing the unique features of femtosecond pulses from a mode locked Ti:sapphire laser such as short pulse duration, high energy density and good coherency, we have encoded micro-holographic optical elements (HOEs) either on or beneath material surfaces. The materials investigated include transparent dielectrics such as single crystals of Al/sub 2/O/sub 3/, SiC, LiNbO/sub 3/, ZrO/sub 2/, ZnO, CaF/sub 2/, CdF/sub 2/, MgO, and TiO/sub 2/, glasses, plastics and metals. Both surface relief type gratings and embedded gratings (refractive index modulation type) were fabricated, respectively, due to laser ablation at surfaces and laser induced structural alterations of materials such as the crystalline to amorphous phase change and chemical bond angle changes in silica glass.