Energy scaling and extended tunability of a ring cavity terahertz parametric oscillator based on KTiOPO4 crystal
Wang Yuye1, 2, Ren Yuchen1, 2, Xu Degang1, 2, †, Tang Longhuang1, 2, He Yixin1, 2, Song Ci3, ‡, Chen Linyu1, 2, Li Changzhao1, 2, Yan Chao1, 2, Yao Jianquan1, 2
       

(color online) Measured (dotted black line) and calculated (blue line) phase matching curves.