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 characterization pulses, providing a reliable foundation for applications in nonlinear spectroscopy, high‐harmonic generation, and related fields.