OPTICAL NANOCOMPOSITES FOR LASER APPLICATIONS

摘要

An optical nanocomposite containing optically active crystals (rare earth or transition metal doped) in a suitably index-, dispersion-, thermo-optically matched matrix enables creation of a glass ceramic with unique optical properties. By further tuning the viscosity of the composite, it can be drawn into fiber form, dissolved into solution and subsequently deposited as a thin film, or used as a bulk optical component. Critical to achieving a viable material is closely matching the attributes needed to not only achieve optical function but to enable fabrication under elevated temperatures (i.e., during fiber drawing) or in unique chemical or thermal environments, such as during deposition as a thin film. This invention uses nanosized crystalline powders (nanocrystals—NC), blended with multicomponent chalcogenide glass (ChG) to form an optical nanocomposite. The blended NC:glass integrates compositional tailoring to enable matching of optical properties (index, dispersion, dn/dT), specialized dispersion methods to ensure homogeneous physical dispersion of NCs within the glass matrix during preparation, while minimizing agglomeration and mismatch of coefficient of thermal expansion. The latter attributes are critical to maintaining low loss (optical scatter) and induced stress birefringence due to mismatch between the NC and glass' parent properties. By tailoring the base glass composition's viscosity versus temperature profile, the resulting bulk nanocomposite can be further formed to create an optical fiber, while maintaining physical dispersion on NCs, avoiding segregation of the NCs. This enables low loss conditions suitable for lasing within the material.