100 kHz linewidth Cr2+:ZnSe ring laser tunable from 2.12 to 2.58 μm

We demonstrate a single-frequency, room temperature Cr2+:ZnSe laser widely tunable in the mid-infrared spectral region from 2.12 to 2.58 μm. Using a compact unidirectional ring cavity configuration, we obtain a maximum output power of 160 mW with an emission linewidth of ∼100  kHz in a 1 ms observation time. As a result, we can accurately report amplitude- and frequency-noise characterizations.