Title :
Widely Tunable, Monochromatic THz Generation via Cherenkov-Type Difference Frequency Generation in an Asymmetric Waveguide
Author :
Pengxiang Liu ; Degang Xu ; Weipeng Wang ; Changming Liu ; Sujia Yin ; Xin Ding ; Yuye Wang ; Jianquan Yao
Author_Institution :
Key Lab. of Opto-Electron. Inf. & Tech. Sci. (Minist. of Educ.), Tianjin Univ., Tianjin, China
Abstract :
Cherenkov-type monochromatic terahertz (THz) generation via difference frequency generation in a general asymmetric sandwich-like waveguide is investigated theoretically. An efficient geometry-conversion from a transverse electric (TE) pump mode to a TE THz mode is mainly considered. The general expression for a Cherenkov THz field is obtained by solving the nonlinear wave equation analytically. Numerical simulation is performed on specific devices with three typical substrate materials: 1) nondoped LiNbO3; 2) BK7 glass; and 3) quartz. Characteristics of this type of THz source and parametric dependence of conversion efficiency are discussed. It is predicted that the conversion efficiency would be increased by one order by optimizing the waveguide structure.
Keywords :
lithium compounds; optical frequency conversion; optical glass; optical waveguides; quartz; terahertz wave generation; wave equations; BK7 glass; Cherenkov-type difference frequency generation; LiNbO3; TE terahertz mode; conversion efficiency; general asymmetric sandwich-like waveguide; geometry-conversion; monochromatic terahertz generation; nonlinear wave equation; quartz; transverse electric pump mode; Frequency conversion; Nonlinear optics; Optical pumping; Optical waveguides; Substrates; Cherenkov phase matching; difference frequency generation; optical waveguide; terahertz generation;
Journal_Title :
Quantum Electronics, IEEE Journal of
DOI :
10.1109/JQE.2012.2234438
