We propose an efficient and compact plasmonic surface-enhanced terahertz generation scheme based on nonlinear difference-frequency generation inside a metal–insulator–metal structure. Gold nanowire arrays are planted on top of the surface of a lithium niobate (LN) substrate with second-order nonlinearity to enhance both the nonlinear wavelength conversion and waveguide terahertz waves at the same time. Our numerical simulations show that our structures are capable of generating both tunable continuous and ultrafast-pulsed terahertz sources. We also discuss further improvements on the conversion efficiency by combining with Ti-diffusing LN waveguides.
© 2014 Optical Society of America
Original Manuscript: March 7, 2014
Revised Manuscript: April 30, 2014
Manuscript Accepted: May 3, 2014
Published: June 11, 2014
Yuanxun Ge, Jianjun Cao, Zhenhua Shen, Yuanlin Zheng, Xianfeng Chen, and Wenjie Wan, "Terahertz wave generation by plasmonic-enhanced difference-frequency generation," J. Opt. Soc. Am. B 31, 1533-1538 (2014)