Roadmap for the next generation of laser-based, high-power THz-Time Domain Spectrometer

This paper presents an overview of the recent results of our group, which utilize high-power Ytterbium-based laser systems to excite various THz emitters. In particular, we have achieved a new THz power record from a tabletop, single-cycle THz source with 643 mW of THz average power at 40 kHz, by cryogenically cooling the inorganic lithium niobate crystal. Despite the relatively narrow bandwidth of sub-2-THz, other sources, such as organic crystals, have demonstrated a recent improvement in performance, particularly in phase-sensitive detection within a THz-time domain spectrometer. In addition to a THz average power exceeding 5 mW, an ultrabroadband bandwidth of over 12 THz has been observed. For high repetition rates, the thin lithium niobate was implemented inside a home-built Kerr-lens mode-locked laser system. The crystal was capable of withstanding the high intracavity power in this proof-of-principle experiment, thereby enabling access to the ten to hundred times higher pump power levels intracavity that would otherwise be inaccessible.