Synthesis and characterization of Cr4+-doped CaO–GeO2–Li2O–B2O3(Al2O3) transparent glass-ceramics

Synthesis and devitrification behavior of Cr-doped CaO–GeO2–Li2O–B2O3(Al2O3) glasses have been studied. A range of glass compositions was found to yield transparent glass-ceramics after devitrification. The size of crystallites is below 1 μm. Glass-ceramic samples exhibit 1050–1600 nm broad-band emission with a maximum around 1260 nm, very similar to the emission of Cr4+:Ca2GeO4 bulk crystals. X-ray diffraction measurements indicate that the structure of crystallites exhibiting near infrared emission in glass-ceramics may be assigned to Cr4+:Ca2GeO4 with increased lattice parameters.