High-Intensity THz Pulses Generation In Lithium Niobate Using A Reflective Echelon Scheme

This work analyzes how the beam size and the repetition rate affect the THz generation efficiency in lithium niobate $\left(\mathrm{LiNbO}_{3}\right)$ using the RES (Refractive Echelon Mirror) configuration. Our THz source is driven by an ytterbium-fibre-based chirped-pulse amplifier system. The system delivers ultrashort pulses of 300fs duration with a maximum energy of 240 μJ at 330 kHz. It is found that by optimizing the pump beam size on the LiNbO
3
crystal, we measure a THz power of 114 mW for 44.5 W pump power at 205 MHz repetition rate, corresponding to a total optical-to-THz efficiency of 0.25%.