Mid-IR lasing of iron–cobalt co-doped ZnS(Se) crystals via Co–Fe energy transfer

We report a spectroscopic characterization of iron–cobalt co-doped ZnS and ZnSe laser crystals over 14–300 K temperature range. Mid-IR Fe2+ lasing via Co–Fe energy transfer was demonstrated under cobalt excitation at 4A2–4T1 transition by 1.56 μm radiation.