High Verdet constant of Te₂₀As₃₀Se₅₀ glass in the mid-infrared

Magneto-optical properties of tellurium-arsenic-selenium glass (${{\rm Te}_{20}}{{\rm As}_{30}}{{\rm Se}_{50}}$Te₂₀As₃₀Se₅₀) were measured and analyzed. A Verdet constant of 15.18 rad/T/m at 1950 nm with the figure of merit of more than 8.72 rad/T, which is the highest value reported in glass materials at this wavelength, was measured. Compared to other chalcogenide glasses, such as ${{\rm Ge}_{10}}{{\rm Se}_{90}}$Ge₁₀Se₉₀ and ${{\rm Ge}_{25}}{{\rm As}_{15}}{{\rm S}_{60}}$Ge₂₅As₁₅S₆₀, ${{\rm Te}_{20}}{{\rm As}_{30}}{{\rm Se}_{50}}$Te₂₀As₃₀Se₅₀ glass exhibits higher Verdet constants, broader mid-infrared transparency window, and longer infrared absorption edge, making it a very promising material to fabricate magneto-optical devices for mid-infrared applications.