Femtosecond mid-infrared difference-frequency-generation tunable between 3.2 μm and 4.8 μm from a compact fiber source

A broadband fiber-based femtosecond laser source, tunable in the mid-IR between 3.2 μm and 4.8 μm, exhibiting a maximum output power of more than 1 mW, and a conversion efficiency of more than 30%, is demonstrated. For experiment commercially available Er:fiber two-branch amplifier laser system is used.