Optical applications of glass-ceramics

Glass-ceramics are usually formed through passing several stages of phase transformations (nucleation, crystallization of metastable and stable crystalline phases). The properties of glass-ceramics depend on at what stage the process was stopped. The phase assemblage of glass-ceramics is controlled by the composition of the initial glass and heat-treatment conditions. Raman and optical spectroscopy, in combination with X-ray diffraction and small angle X-ray scattering techniques are used to study the behavior of the nucleation and crystallization of lithium, magnesium and zinc aluminosilicate glasses. Specific heat-treatments has given the opportunity to achieve a desired phase assemblage ensuring unique properties of glass-cerathics by interrupting the process at a certain stage. Examples of such glass-ceramic developments include thermal shock resistant color filters, passive Q-switchers for eye-safe Er:glass lasers. as well as transparent materials based on rare-earth titanates with pyrochlore structure with luminescence in the range of 1.5 mu m. The approach to developing the dual active-passive media for the eye-safe spectral region is demonstrated for the first time. (C) 2010 Elsevier B.V. All rights reserved.