In high purity C e 3 + -doped selenide glass pumped by a 4.08 µm Fe:ZnSe laser, 5.1–5.5 µm laser oscillations were observed. This is the first evidence of laser action corresponding to the 2 F 7 / 2 → 2 F 5 / 2 transition of C e 3 + ions.

A study of Yb:GdCOB under diode-bar pumping has been performed and the results are compared, experimentally and theoretically, with Yb:KGW in the same cavity. An output power of 7.3 W and a slope efficiency of 57.4% were obtained. Self-frequency-doubling experiments are also discussed.

High-purity samples of the new Ge₃₆Ga₅Se₅₉ glass composition doped with 2×10¹⁹, 5×10¹⁹ and 10²⁰ cm⁻³ of Pr³⁺ atoms were synthesized and their luminescent properties were investigated in the 1.6–7.5 µm spectral range. The luminescence registration method involved has made it possible to separate the spectra of the overlapping transitions in Pr³⁺ in the 2–2.7 µm emission band and to determine the respective lifetimes as well as their concentration dependencies. High sensitivity of the detection system has allowed to detect weak luminescence band at ∼7.2 µm corresponding to ³F₃→³F₂ transition for the first time in Pr doped glasses. The experiments showed that intense cross-relaxation processes in investigated glasses can cause a steep ∼ 5 µm emission rise with Pr³⁺ concentration increase. This effect can be of use for the design of efficient ∼ 5 µm luminescent sources with population efficiency significantly exceeding 100% (when pumped at ∼ 1.5 µm) and luminescence quantum yield close to unity.

Energy, spectral and temporal characteristics of a Ce³⁺-doped chalcogenide glass fiber laser continuously pumped by a 4.16 μm Fe²⁺:ZnSe laser were investigated. Milliwatt level output power was obtained. In case of low Q-factor of the resonator the laser operated at λ = 4.62 μm corresponding to the narrow peak in Ce³⁺ emission spectrum. At higher Q-factor, the lasing wavelength changed to 5.0–5.1 μm corresponding to the plateau in the gain spectrum. In contrast to Tb³⁺-doped mid-infrared fiber lasers, Ce³⁺-doped fiber laser had no tendency to non-relaxing spike operation.

This paper provides an overview of mid-infrared lasers based on rare-earth-ion-doped selenide glasses. Laser action was demonstrated at the transitions between the first excited and the ground levels of Ce³⁺, Pr³⁺, Nd³⁺ and Tb³⁺ ions. The highest output parameters for bulk glass lasers (over 40 mJ of output energy) and wavelength tuning in the range of 4.6–5.6 microns were obtained with Ce³⁺-doped glass. The highest output parameters for fiber lasers (150 mW at 5.1–5.3 μm under continuous pumping) were demonstrated with Tb³⁺ ions. The longest lasing wavelengths for any glass laser and tunability within the 5.56–6.01 µm spectral band were shown with Nd³⁺ ions in a Tb³⁺-Nd³⁺ co-doped system.