High average power diode-side-pumped intracavity terahertz parametric source based on stimulated polariton scattering in RbTiOPO4 crystal

This paper reports an intracavity terahertz parametric source based on the stimulated polariton scattering in RbTiOPO4 crystal with a high repetition rate and a high average power. The side pumping for the gain medium by laser diodes is adopted to get a higher fundamental power and a larger fundamental laser beam size than those in the diode-end-pumping in order to improve the THz output power. A non-collinear convex-plane fundamental cavity is adopted so that the thermal effect can be offset in some degree and the fundamental beam size is further increased. The obtained maximum average THz output power is 367 μW at 3.88 THz when the diode pump power is 105 W and the pulse repetition frequency (PRF) is 7 kHz. The terahertz power of 367 μW is the highest ever obtained in SPS sources.