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New laser applications as medicine treatment, air pollutants measurement, free-space communications, target illumination, and industrial technologies require laser radiation in the mid-infrared region of 4–6 μm where Fe2+-based lasers can generate. Pumping of Fe2+-doped active material is usually provided by sources generating near 3 μm (as YAG:Er, Er-fiber, or ZnSe:Cr) fitting the Fe2+ absorption maximum. Other promising pumping way is the energy transfer from Cr2+ to Fe2+ in co-doped materials. This energy transfer process in gain-switched operation under 200 ns, 1.73 μm pulse excitation was reported recently. In this paper we would like to present 1 ms, 10 Hz laser operation of the Zn1-xMnxSe:Fe2+,Cr2+ (x = 0.3) crystal within the 78–110 K temperature range under 1.94 μm commercial Tm:fiber laser pumping. The active crystal was placed in the cryostat and the cavity was formed by a curved dichroic pumping mirror and a curved output coupler. The slope efficiency of 1 % was achieved for 1.94 μm pumping at 78 K. The central laser output wavelength at 78 K was ~4.45 μm and the output spectrum temperature shift was about 2 nm/K. Furthermore, tunability range over 300 nm (4.35–4.67 μm) obtained at 78 K using intracavity tuning element. The results will be compared to an analogous Zn1-xMnxSe:Fe2+ (x = 0.3) crystal in a gain-switched mode under Q-switched YAG:Er3+ 2.94 μm laser pumping. Moreover, laser generation of crystals with different Mn concentration and CW generation will be also presented.
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