Terahertz radiation based on fiber-pigtailed InGaAs photoconductive antenna pumped by 1030 nm mode-locked Yb-doped fiber laser

We present a terahertz (THz) radiation pumped by a passively mode-locked Yb-doped fiber laser using two fiber-pigtailed log-spiral-based low-temperature-grown (LTG) InGaAs photoconductive antenna (PCA) modules. The mode-locked fiber laser produces over 220 mW of the average optical power with positively chirped of 1.49 ps pulses. In order to generate THz radiation using the fiber-pigtailed PCA modules, the mode-locked optical pulses are pre-chirped with 538 fs using two diffraction gratings. We successfully achieved THz radiation over 2.0 THz using the pre-chirped pulses. We successfully observed the various absorption lines of water vapor dips in the free space of 120 mm.