Transparent glass-ceramics for optical applications

The design, properties, and applications of transparent glass-ceramics are reviewed. Interference effects in light scattering by transparent glass-ceramics are discussed. The scattering coefficient of transparent glass-ceramics is found to be significantly less than that for the case of independent Rayleigh scattering by nanocrystals; its wavelength dependence is qualitatively different. A reduction in interference effects achieved by precipitation of nanocrystals of different crystalline phases with different scattering properties results in glass-ceramics with high diffuse reflection. The origin of the low coefficient of thermal expansion of glass-ceramics is discussed based on the temperature dependence of the unit cell parameters of beta-quartz solid solutions measured by in situ high-temperature x-ray diffraction. Transparent glass-ceramics doped with Co2+ and Ni2+ ions for thermal shock-resistant color filters, for broadband near-infrared (IR) optical amplifiers, and for passive Q-switching of eye-safe Er lasers are presented. Glass-ceramics with rare-earth titanates, titanates-zirconates, and niobates in dual roles of nucleators and active crystals are reviewed.