The Investigation on the Beam Spatial Intensity Distributions in the Injection-Seeded Terahertz Parametric Generator

• Main Authors: Jie Zang, Dong Wu, Xingyu Zhang, Zhenhua Cong, Zengguang Qin, Xiaohan Chen, Zhaojun Liu, Ping Li, Feilong Gao, Chenyang Jia, Yue Jiao, Weitao Wang, Shaojun Zhang
• Format: Article
• Language: English
• Published: IEEE 2019-01-01
• Series: IEEE Photonics Journal
• Subjects: Terahertz radiation; nonlinear optics; stimulated polariton scattering; LiNbO<inline-formula xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <tex-math notation="LaTeX">$_{3}$</tex-math> </inline-formula>
• Online Access: https://ieeexplore.ieee.org/document/8666788/

In terahertz (THz) wave parametric sources, the large angle between the pump and terahertz waves (about 65&#x00B0; in LiNbO₃ crystal) will affect the spatial intensity distributions. To investigate how the noncollinear phase-matching affects the spatial intensity properties of the pump, Stokes, and THz waves, we take the injection-seeded THz-wave parametric generator (is-TPG) as an example to study the beam spatial intensity properties via the numerical solutions of the coupled-wave equations. The simulated results demonstrate that the pump and Stokes intensities have significant changes along the THz-wave propagation direction. It is the first time that the spatial intensity distributions of the three waves in the THz-wave parametric sources have been studied in theory. In addition, the output intensity distributions of the pump, Stokes, and THz waves are measured in the designed is-TPG. The measured spatial intensity distributions are in coincidence with the simulated results. Investigations on the beam spatial intensity properties provide a potential approach to improve the THz-wave outputs and the pump conversion efficiency for the is-TPG and other THz-wave parametric sources.