Cascaded stimulated polariton scattering in a dual-Stokes cavity terahertz parametric oscillator

Terahertz polariton sources based on the stimulated polariton scattering (SPS) can generate the terahertz wave with a narrow linewidth and continuous tunability. A single SPS process has limited conversion efficiency due to the Manley-Rowe relation. In this Letter, we implement a dual-Stokes cavity structure within an intracavity terahertz parametric oscillator (TPO) to achieve a two-order cascaded SPS process. As a result, the dual-Stokes cavity TPO demonstrates an increment of 29% in terahertz output power compared to that obtained in the non-cascaded SPS configuration.