Dynamics of mid-infrared semiconductor switching controlled by femtosecond laser pulses

Semiconductor switching of sub-picosecond mid-infrared laser pulses between 10 and 14 µm is characterized in GaAs, n-Ge, and ZnSe controlled by 30 fs pulses with photon energy above the band gap of the material. The reflectivity and lifetime are studied for multiple wavelengths. Time domain dynamics of semiconductor plasma reflectivity observed in experiments correlate with that derived in diffusion-recombination theory. Potential application of ultrafast semiconductor switching as a photonic device for use in high-power mid-infrared laser systems is discussed.