Compact solid-state laser systems based on chromium doped II-VI semiconductor materials (ZnS, ZnSe, CdSe) with
tunability over 2-3.6 μm, output power exceeding 10W, and efficiency up to 70% were demonstrated recently. A further
increase of the output power requires a thorough thermal management of the active element. Fiber geometry of gain
element is very promising among other different approaches to control beam quality and thermal lensing. The proposed
transition metal doped ZnS:ZnSe/As2S3:As2Se3 composite materials with index matching of II-VI and V-VI components
represent a new way for design of mid-infrared laser active fibers. Chalcogenide glasses have wide transparency range in
mid-IR, enable fiber geometry, and their refractive index can be varied from n=2.1 to n=2.5 matching refractive index of
ZnS (n=2.26) and ZnSe (n=2.44) crystals and eliminating scattering losses. The II-VI compounds provide a tetrahedral
coordination of the chromium ions required for mid-IR lasing. We report the first mid-IR laser active
Cr:ZnSe/As2S3:As2Se3 composites fabrication and room-temperature lasing at 2.4 μm. The Cr:ZnSe/As2S3:As2Se3 composites were prepared by annealing of the appropriate compounds under vacuum and by casting and drying of
Cr:ZnSe microparticles suspension in As2S3:As2Se3 propylamine solution. All samples demonstrated mid-IR
photoluminescence typical for Cr2+ ions in ZnSe host. High optical gain and low passive losses in Cr:ZnSe/As2S3:As2Se3 composite material were demonstrated in random lasing experiments.
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