High-repetition-rate injection-seeded terahertz-wave parametric generation pumped by a 1.5 μm sub-nanosecond laser

Abstract

Injection-seeded terahertz (THz)-wave parametric generation (is-TPG) using a nonlinear optical crystal of MgO-doped lithium niobate (MgO:LiNbO3) has made it possible to obtain THz waves with high peak powers and narrow linewidths. To achieve stable THz-wave generation from the MgO:LiNbO3 crystal under strong excitation, the photorefractive effect in the MgO:LiNbO3 crystal would be crucial, which could be eliminated by using a longer pump wavelength than the conventional 1-μm spectral band. Here, we propose to use a 1.5-μm near-infrared (NIR), high-repetition-rate, sub-nanosecond laser source based on a unique Er,Yb:glass planar waveguide amplifier (PWA) as the pump source for the is-TPG using the MgO:LiNbO3 crystal. At a repetition rate of 25 kHz, the frequency tunability from 1.3 to 2.5 THz was obtained with a maximum THz-wave average output power of 0.14 mW at 1.77 THz.