Compact Fiber-Pumped Terahertz Source Based on Difference Frequency Mixing in ZGP

We have demonstrated a novel terahertz source based on dual-wavelength amplification in polarization maintaining Yb- doped fiber and frequency mixing in a zinc germanium phosphide (ZGP) crystal. The system consists of two orthogonally polarized signals, whose difference frequency is in the terahertz region, amplified in a single all-fiber amplifier chain and mixed in a ZGP crystal to generate high-peak-power terahertz radiation. Currently, 2 mW of average terahertz power (20 W peak, 20 nJ/pulse) has been produced at a repetition rate of 100 kHz and pulsewidths of 1 ns with a conversion efficiency of 0.137%. We have also developed a terahertz mixing model, which coincides well with our experimental data.