Midinfrared emission properties of Pr3+-doped chalcogenide glasses at cryogenic temperature

Abstract

Low-temperature midinfrared emission properties of Pr3+-doped Ge30Ga2As6S62 and Ge28Ga5As12Se55 glasses (at. %) were investigated. Emissions centered at 3400 and 4700 nm were clearly observed from sulfide and selenide glasses, respectively, when the specimens were cooled to 20 K. The measured lifetime of the G41 level in sulfide glass increased from 320 μs at room temperature to 400 μs at 20 K. The intensity and quantum efficiency of the emission from the Pr3+:(3F3, 3F4) level in selenide glass also increased as the temperature decreased to 120 K. The enhancement resulted from a decrease in nonradiative multiphonon relaxation at low temperatures. The temperature dependence of the multiphonon relaxation rates indicated that the asymmetrical stretching vibration of GeS4 tetrahedra (375 cm−1) is primarily responsible for the multiphonon relaxation process in sulfide glass.