High energy Yb:CaF_2 femtosecond laser for efficient terahertz generation in lithium niobate

摘要

We investigated intense Terahertz generation in lithium niobate pumped by a powerful Yb:CaF_2 laser at room temperature and 25 K. This unique amplifier system delivers transform-limited pulses of variable duration (0.38-0.65 ps) with pulse energies up to 12 mJ at a central wavelength of 1030 nm. From theoretical investigations it is expected that those laser parameters are excellently suited for efficient THz generation. In this study we present experimental results on both the conversion efficiency and the THz spectral shape for a series of transform-limited pump pulse durations and crystal temperatures and discuss the optimum pump parameters for most efficient THz generation.