RESUMO
Two different mid-infrared (mid-IR) solid-state crystalline laser active media of Cr2+, Fe2+:Zn1-xMnxSe and Cr2+, Fe2+:Zn1-xMgxSe with similar amounts of manganese or magnesium ions of x ≈ 0.3 were investigated at cryogenic temperatures for three different excitation wavelengths: Q-switched Er:YLF laser at the wavelength of 1.73 µm, Q-switched Er:YAG laser at 2.94 µm, and the gain-switched Fe:ZnSe laser operated at a liquid nitrogen temperature of 78 K at â¼4.05 µm. The temperature dependence of spectral and laser characteristics was measured. Depending on the excitation wavelength and the selected output coupler, both laser systems were able to generate radiation by Cr2+ or by Fe2+ ions under direct excitation or indirectly by the Cr2+â Fe2+ energy transfer mechanism. Laser generation of Fe2+ ions in Cr2+, Fe2+:Zn1-xMnxSe and Cr2+, Fe2+:Zn1-xMgxSe (x ≈ 0.3) crystals at the wavelengths of â¼4.4 and â¼4.8 µm at a temperature of 78 K was achieved, respectively. The excitation of Fe2+ ions in both samples by direct 2.94 µm as well as â¼4.05 µm radiation or indirectly via the Cr2+â Fe2+ ions' energy transfer-based mechanism by 1.73 µm radiation was demonstrated. Based on the obtained results, the possibility of developing novel coherent laser systems in mid-IR regions (â¼2.3-2.5 and â¼4.4-4.9 µm) based on AIIBVI matrices was presented.
RESUMO
Millisecond-pulse laser operation of Fe2+ ions at 78 K is demonstrated in the Zn1-xMnxSe:Fe2+,Cr2+ (x=0.3) crystal under a Tm fiber 1940 nm laser pumping through a Cr2+âFe2+ energy transfer process for the first time, to the best of our knowledge. The laser slope efficiency was 1% with respect to absorbed pumping energy at 1940 nm. The laser central wavelength shift from 4450 nm at 78 K up to 4510 nm at 110 K was observed. Tunability from 4350 up to 4670 nm at 78 K was achieved using an intracavity tuning element.