High Average Power Large-Area Photoconductive Emitter at 400 kHz Repetition Rate

The generation of high-power single-cycle terahertz (THz) radiation has attracted considerable interest for applications in imaging, spectroscopy, and material analysis. Achieving a high dynamic range (DR) within short measurement times requires high average power at high repetition rates, compatible with fast acquisition methods. Efforts to scale THz power through optical rectification in nonlinear crystals have resulted in watt-level outputs [1], but they involve complex phase-matching and high-energy laser systems. Alternatively, large-area photoconductive emitters with interdigitated electrodes (LAE) [2], [3], driven by high-average powerultrafast lasers, offer a promising alternative for average power scaling. However, achieving high conversion efficiency while managing thermal load remains a challenge at very high MHz repetition rates [4]. Furthermore, exploiting the full THz average power potential to increase dynamic range via averaging, requires high-power Yb-lasers with very low noise, which are currently still in development.