Generation and Spatio-Temporal Characterization of High-Repetition-Rate High-Peak-Power Long-Wave Infrared Laser Pulses

Emerging as essential tools for interrogating ultrafast nonequilibrium processes in quantum materials, ultrashort long-wavelength infrared (LWIR) pulses demand both high performance and fine characterization. In this letter, we present a high-repetition-rate (50 kHz) LWIR source with peak fields exceeding 14.8 MV cm-1 and spectral tunability (8-12.5 μm), generated via difference frequency generation scheme between a Yb:YAG pump laser and its parametrically amplified signal. Spatio-temporal coupling pulse characterization is realized through nonlinear optical imaging of time-resolved four-wave mixing between LWIR and near-infrared pulses in a 1-μm-thick silicon film. The multi-dimensional pulse characterization confirms the excellent temporal characteristics and high beam quality of the generated LWIR pulses, providing a reliable foundation for applications in nonlinear spectroscopy, high-harmonic generation, and related fields.