High-repetition-rate tunable narrowband terahertz-wave generation based on nonlinear frequency conversion pumped by dual fiber lasers in MgO:LiNbO3

We demonstrate a high-average-power, single-longitudinal-mode, and tunable terahertz-wave (THz-wave) source based on difference frequency generation (DFG) in a MgO:LiNbO3 (MgO:LN) crystal. The DFG waves are generated using a pair of Yb-doped, pulsed fiber lasers with a master oscillator power fiber amplifier configuration. The average power of the THz-wave output reaches 1.35 mW at 1.0 THz (300 mu m) at a linewidth of 7.2 GHz, and the tunability ranges from 0.34 to 1.25 THz under a pulse repetition frequency of 500 kHz. With this scheme, we constructed a compact THz-wave generation head for imaging applications. The combination of MgO:LN-DFG and the stable and robust fiber laser sources is highly promising for developing high-average-power THz-wave sources, particularly in the high-transmission sub-THz region. This approach may enable new applications of THz-wave spectroscopy in imaging and remote sensing.