Frequency-Tunable THz Source Based on Stimulated Polariton Scattering in ${\rm Mg{:}LiNbO}_{3}$

We report a very compact, laser diode end-pumped THz laser source, which utilizes two resonators to generate frequency-tunable radiation across the range 1.53-2.82 THz via stimulated polariton scattering (SPS) in a Mg:LiNbO
₃
crystal. To the best of our knowledge, this THz system operates with the lowest pump power threshold (2.4 W), and highest conversion efficiency (6.45ţW average output power at 1.82 THz for 5 W input diode pump power) ever reported for a THz source based on SPS.