Ultra-widely tunable high-power terahertz parametric generation based on synchronized sub-nanosecond pump and nanosecond seeder

Terahertz parametric generation (TPG) is one of the most promising techniques for developing high-performance terahertz sources, particularly through the use of sub-nanosecond laser pumping that simultaneously suppresses stimulated Brillouin scattering and enhances nonlinear gain. However, a fundamental challenge persists in achieving both high output power and broad tunability due to the lack of efficient seeding solutions. This study demonstrates a novel, to our knowledge, approach to address this issue, employing a high-power sub-nanosecond pump laser and a synchronized tunable nanosecond optical parametric oscillator (OPO) seeding system. The terahertz-wave tuning range of 0.55–13.6 THz was enabled by integrating two nonlinear crystals (MgO:CLN and KTP) and dual pump wavelengths (1064 and 532 nm). Operating at the repetition rate of 1 kHz, the maximum output power reached 1.06 mW at 1.68 THz with the peak power exceeding 1 kW, corresponding to the conversion efficiency of 1.25×10 −4 and photon conversion efficiency of 2.1%. The TPG system offers high-power stability and good Gaussian beam profile, which is believed to be a significant leap of high-performance terahertz sources and holds great importance in applications like radar, imaging, and spectroscopy. An in-depth analysis was also given on the output characteristics according to the dynamics of the nonlinear processes, paving the way for power scaling.