Advanced nanocomposite materials for optical applications

Using a nanocomposite structure, novel optical materials have been developed with applications ranging from all optical switches for use in optical computing to transparent scratch resistant coatings. The nanocomposites have been constructed by embedding particles of a material with the desired optical property into a matrix which will lend processability and transparency to that material. Possible particle phases include semiconductors, solid state lasers, silica, and magnetic materials. Matrix materials can be polymers, copolymers, polymer blends, glasses, or ceramics. Technologically important films and fibers can be prepared as nanocomposites from materials which are traditionally difficult to process in these forms.;Secondly, novel transparent materials with improved mechanical properties have been developed by incorporating silica into polyimides. Transparent materials were synthesized which showed increased hardness and modulus with increasing silica content. Microstructural investigation showed very small domain sizes in the composites which led to the desired transparency without refractive index matching. Finally, polymer matrix composites containing PbS, a semiconductor with ;Three specific systems of interest will be discussed. Extensive work has been done with solid state lasers embedded in copolymer matrix materials. In these composites, the refractive index of the matrix was matched to that of the laser material to avoid Rayleigh scattering. Both Cr-forsterite and Cr-diopside were studied for their solid state laser properties in the near IR. The laser particles were produced using dispersion polymerized precursors which acted as size templates for the resulting ceramic particles. This novel type of ceramic particle synthesis has broad applications in optical composites and beyond. The matrix materials were prepared by copolymerization of two monomers bracketing the desired refractive index. In this way the refractive index of the copolymer matrix is controlled by the monomer feed composition resulting in polymers which can be tuned to within 0.01 of the desired refractive index. Composite films showed significant laser amplification properties which could be important for optical communications.