Generation of high repetition rate THz radiation at the mill-watt-level via optical rectification in an enhancement cavity

Abstract

We propose an experimental method for the generation of coherent terahertz radiation in the spec-tral region between 0.2 THz and 2 THz, with a high repetition rate of nearly 100 MHz, and with an average power at the milliwatt level. An Ytterbium-doped mode locking laser is amplified to 60 W, and pulses are stacked into an optical cavity up to 750 W. There, they interact with a Gallium Phosphide crystal producing THz radiation via optical rectification. With the cavity enhanced configuration, we show that more than one order of magnitude can be gained with respect to simply focalize the 60 W beam into the GaP crystal.