Cherenkov-type phase matched terahertz wave generation from LiNbO3 waveguide using mode-locked fiber laser and optical amplifier

We demonstrate Cherenkov-type phase-matched terahertz wave generation using a LiNbO3 waveguide that incorporates a half-conic silicon prism, which efficiently generates broadband terahertz waves in a frequency range up to 7 THz with a pulse duration of 146 fs. We use a newly developed environmentally stable passively mode-locked fiber laser and an optical amplifier as a pulse compressor to generate stable high-intensity ultra-short pulses. As a result, optical pulses with a 50-fs pulse duration, an average output power of 50 mW, and a repetition rate of 50 MHz can be successfully generated.