Enabling high repetition rate nonlinear THz science with a kilowatt-class sub-100 fs laser source
Patrick L. Kramer, Matthew K. R. Windeler, Katalin Mecseki, Elio G. Champenois, Matthias C. Hoffmann, Franz Tavella
Abstract
Manipulating the atomic and electronic structure of matter with strong terahertz (THz) fields while probing the response with ultrafast pulses at x-ray free electron lasers (FELs) has offered unique insights into a multitude of physical phenomena in solid state and atomic physics. Recent upgrades of x-ray FEL facilities are pushing to much higher repetition rates, enabling unprecedented signal-to-noise ratio for pump probe experiments. This requires the development of suitable THz pump sources that are able to deliver intense pulses at compatible repetition rates. Here we present a high-power laser-driven THz source based on optical rectification in LiNbO 3 using tilted pulse front pumping. Our source is driven by a kilowatt-level Yb:YAG amplifier system operating at 100 kHz repetition rate and employing nonlinear spectral broadening and recompression to achieve sub-100 fs pulses with pulse energies up to 7 mJ that are necessary for high THz conversion efficiency and peak field strength. We demonstrate a maximum of 144 mW average THz power (1.44 μ J pulse energy), consisting of single-cycle pulses centered at 0.6 THz with a peak electric field strength exceeding 150 kV/cm. These high field pulses open up a range of possibilities for nonlinear time-resolved THz experiments at unprecedented rates.