Abstract-Terahertz Radiation from Combined Metallic Slit Arrays

Dazhi Li, Makoto Nakajima, Masahiko Tani, Jinfeng Yang, Hideaki Kitahara, Masaki Hashida, Makoto Asakawa, Wenxin Liu, Yanyu Wei,  Ziqiang Yang,

https://www.nature.com/articles/s41598-019-43072-2

We report an approach to efficiently generate terahertz radiation from a combined periodic structure. The proposed configuration is composed of two metallic slit arrays deliberately designed with different periodic length, slit width and depth. We found that the combination of the two slit arrays could provide special electromagnetic modes, which exhibit nonradiative property above the surface of one slit array and radiative property inside the other one. An electron beam holding proper energy could resonate with those modes to generate strong and directional electromagnetic radiations in the terahertz regime, indicating that the approach has the potential in developing high-performance terahertz radiation sources.

Abstract-Directional linearly polarized terahertz emission from argon clusters irradiated by noncollinear double-pulse beams

 Kazuaki Mori, Masaki  Hashida, Takeshi  Nagashima, Dazhi Li, Kensuke Teramoto, Yoshihide Nakamiya, Shunsuke Inoue, Shuji Sakabe,

http://aip.scitation.org/doi/abs/10.1063/1.4991736

It has been demonstrated that the interaction between argon clusters and intense femtosecond double laser pulses with appropriate intervals in time and space provides important properties for terahertz electromagnetic wave generation, namely, high forward directivity, power enhancement, and linear polarization with a variable direction. Irradiating argon clusters with double pulses (1 and 3 mJ, 40 fs, 810 nm) in 133-ps and 40-μm intervals results in terahertz wave emission in the forward direction that is 10 times greater than that for a single pulse. The polarization direction of terahertz electromagnetic waves can be varied by changing the relative focal positions of the first and second pulses.