Investigation of MgF2 optical thin films with ultralow refractive indices prepared from autoclaved sols.
We have successfully developed a process to form high quality MgF(2) thin films with ultralow refractive indices from autoclaved sols prepared from magnesium acetate and hydrofluoric acid. And we have confirmed that our porous MgF(2) coatings have not only high transmittance in the UV region but also high uniformity of film thickness. They can be uniformly formed on phiv 300 mm substrates as a single coating and as a hybrid coating with sublayers formed by physical vapor deposition. They are expected to be applied to various optics that need high transmittance in the UV region.
Sol-Gel Route to Inorganic Fluoride Nanomaterials with Optical Properties
A sol-gel method, which is the most significant wet process to prepare solids from liquids, can offer interesting and useful routes for synthesizing inorganic metal fluoride and oxyfluoride materials for applications in optics and photonics. Formerly, heavymetal fluoride glasses were intensively studied for potential use in optical fibres. Now the method is extended to prepare a variety of metal fluorides such as alkaline earth and rare-earth fluorides and oxyfluorides in the form of nanoparticles, thin films and nanocomposites. They can be utilized as antireflective coatings, luminescent materials, VUV materials, IR materials, etc. This chapter describes fundamentals and possible applications of optically useful inorganic fluoride nanomaterials through the sol-gel method.
Graphs of polyhedra; polyhedra as graphs
Relations between graph theory and polyhedra are presented in two contexts. In the first, the symbiotic dependence between 3-connected planar graphs and convex polyhedra is described in detail. In the second, a theory of nonconvex polyhedra is based on a graph-theoretic foundation. This approach eliminates the vagueness and inconsistency that pervade much of the literature dealing with polyhedra more general than the convex ones.