Fig. 1. Structural diagram of Fe∶ZnSe CW laser

Fig. 2. Transmittance curve of coated Fe∶ZnSe crystal

Fig. 3. Output power of 3.8 µm laser versus injected pump power at low temperature with output power curve of 2.8 µm laser shown in inset

Fig. 4. Output spectra of Fe∶ZnSe laser at different output

Fig. 5. Fluorescence emission spectra of Fe∶ZnSe crystal at different temperatures^[35]

Fig. 6. Output power curve of long running laser with far-field light spot of 3.8 μm laser shown in inset