(KTP) crystal is used as the nonlinear medium in a surface-emitted terahertz-wave parametric oscillator for the first time. The oscillating Stokes beam propagates along the axis of the KTP crystal, the pumping beam propagates with a small incident angle to the axis, and the polarizations of the pumping beam, the Stokes beam, and the THz wave are along the axis. When is changed from 1.250° to 6.000°, the THz wave is intermittently tuned from 3.17 to 3.44 THz, from 4.19 to 5.19 THz, and from 5.55 to 6.13 THz. The maximum output of the THz wave is 336 nJ, obtained at 5.72 THz with a pumping energy of 80 mJ. The two frequency gaps, from 3.44 to 4.19 THz and from 5.19 to 5.55 THz, are located in the vicinities of the modes of and , which are strongly infrared absorbing.
© 2014 Optical Society of America
(190.4410) Nonlinear optics : Nonlinear optics, parametric processes
(190.5890) Nonlinear optics : Scattering, stimulated
Original Manuscript: March 12, 2014
Manuscript Accepted: May 18, 2014
Published: June 16, 2014
Weitao Wang, Zhenhua Cong, Xiaohan Chen, Xingyu Zhang, Zengguang Qin, Guanqi Tang, Ning Li, Cong Wang, and Qingming Lu, "Terahertz parametric oscillator based on KTiOPO4 crystal," Opt. Lett. 39, 3706-3709 (2014)