Femtosecond Cr:ZnS laser at 2.35 µm mode-locked by carbon nanotubes

We report the solid-state Cr:ZnS laser mode-locked by CNT-based saturable absorber. The absorber was deposited on a protected silver mirror used as a high reflector mirror in a standard 250-MHz cavity with chirped mirror GDD compensation. Laser pulses with duration of 61 fs were obtained at 2.35 μm wavelength. The output power was limited at 950 mW, corresponding to the pulse energy of 3.8 nJ. We have demonstrated the longest-wavelength mid-IR CNT-mode-locked laser with record parameters, advancing the carbon nanotube mode-locking technology well beyond 2 μm into the mid-IR