Chalcogenide glasses and glass-ceramics for novel infrared optical technologies

Summary form only given. Chalcogenide glasses have been studied for their wide transmission range which can extend from visible up to 20 mum covering the two atmospheric windows of 3 - 5 mum and 8 - 12 mum. These two windows are strategic for night vision. Associated with the possibility of producing infrared optics by high precision molding, these materials are now used for thermal imaging especially when low cost optics are necessary. Optical fibers have also been drawn from these glasses and potential applications include chemical and biologic sensing, laser power delivery and modal filtering. A new class of infrared transmitting glass ceramics has also been developed by combining chalcogenide and halide. By controlling the nucleation and crystal growth, glass-ceramics containing nanocrystals have been reproducibly obtained. These composite materials exhibit much stronger resistance to fracture propagation. Chalcogenide glasses are also known for their very low phonon energy and are considered as highly efficient host for rare earth doping. Chalcogenide based glass ceramics can combine the possibility of easy shaping of a glass and the favorable crystalline environment for the rare earth, created by the nanocrystals in the glass matrix. With these materials, high quantum efficiency can be obtained for frequency conversion. Potential applications will be discussed.