Long-Wave IR Luminescence of Tb³⁺ and Sm³⁺ doped Ga5Ge20Sb10Se65 Fibers

Chalcogenide glasses transparency properties and their use for various applications in the Mid-Wave InfraRed (MWIR, 3-5 μm) and Long-Wave IR (LWIR, 8-12 μm) spectral domains are well-known. Specific chalcogenide glasses composition can be advantageously doped with rare-earth (RE) ions and because of their low phonon energy they are likely to provide infrared luminescence from the RE low lying manifolds. We present here for the first time to the best of our knowledge, the RE luminescence in the LWIR domain of Sm ³⁺ and Tb ³⁺ ions in a selenide-based glass (Ga ₅ Ge ₂₀ Sb ₁₀ Se ₆₅ ). 500 ppm and 1000 ppm Sm ³⁺ and Tb ³⁺ doped Ga ₅ Ge ₂₀ Sb ₁₀ Se ₆₅ optical fibers of high purity and optical quality were elaborated from conventional methods. Absorption and emission properties of the low-lying Sm ³⁺ and Tb ³⁺ manifolds in this low-phonon energy glass host were investigated in details (Fig. 1). In the case of Sm ³⁺ , the low-lying manifolds emissions in the LWIR domain could potentially result in a four-level laser operation in the 6-8 μm region. The Tb ³⁺ ion lower manifolds ( ⁷ F _0→6 ) also offer potential mid-IR transitions in this glass.