Demonstration of 0.6 mJ Multicycle THz Pulses Via Chirp-and-delay Down Conversion of Broadband Lasers with Precise Spectral Phase Tuning and Large PPLN

Millijoule-scale multicycle terahertz (THz) sources have recently gained interest for applications where high-peak-fields and narrow bandwidths can produce unique results, such as linear and nonlinear spectroscopy, control of matter, and compact electron acceleration. Difference frequency generation (DFG) using periodically-poled lithium niobate (PPLN) is a very promising method for producing such pulses, due to the high nonlinear coefficient of lithium niobate and the tunability of the periodic poling. For optimized configurations of laser drivers and PPLN crystals, theoretical predictions show conversion efficiencies of 1% and higher can be reached. Using Joule-scale optical pulses may thus make 10s of mJ multicyle THz pulses possible.