High-repetition rate, mid-infrared, picosecond pulse generation with μJ-energies based on OPG/OPA schemes in 2-μm-pumped ZnGeP₂

We report on two different concepts to generate µJ-level mid-infrared laser pulses with sub-10 ps pulse duration via nonlinear parametric generation at high pulse repetition rates. Both schemes rely on the recent development of compact and efficient CPA-free, Ho:YLF-based 2-µm laser sources pumping the highly nonlinear crystal ZnGeP2 used for parametric amplification. The first concept comprises a simplified OPG/OPA scheme efficiently producing signal and idler radiation at fixed wavelengths of 3.0 and 6.5 µm, respectively. In the second concept, we demonstrate a wide spectral tunability of the picosecond, µJ pulses over the entire tuning range between 2.5 and 12 µm maintaining a constant bandwidth of sub-20 cm−1 by integrating a two-color pumping scheme and a spectral shaper into the setup. The presented compact and efficient mid-IR picosecond radiation sources offer a way towards low-cost mid-IR material processing and spectroscopic applications.