Abstract-Controlling the terahertz radiation with subwavelength blocky patterned CoFeB/Pt heterostructures

Bangju Song, Yuna Song, Shunnong Zhang, KaiLong Jin, Weihua Zhu, Qin Li, Zongzhi Zhang, Xian Lin, Ye Dai, Xiaona Yan,

https://iopscience.iop.org/article/10.7567/1882-0786/ab4d2b/pdf

We report the broadband emission of THz pulse in the metallic patterned ferromagnetic heterostructures CoFeB/Pt based on inverse spin-Hall effect, by illuminating a train of linearly polarized 120 fs-wide laser pulses at 800 nm. The spatial-temporal distribution of charge currents by changing the length of the subwavelength rectangular metal-blocks allows not only effectively controlling the magnitude, but also subtly tuning the center frequency and bandwidth of the emitted THz pulses. Our results will open new avenues for the study of modulated spintronic-based THz emitters.

Abstract-Dark mode tailored electromagnetically induced transparency in terahertz metamaterials

Kailong Jin, Xiaona Yan, Xiaoyan Wang, Wenjie Zhang Zuanming JinYe,  Dai Guohong Ma, Jianquan Yao

https://link.springer.com/article/10.1007/s00340-019-7174-3

In this paper, a novel terahertz metamaterial structure composed of a pair of sub-wavelength reverse U-shaped split ring resonators (RUSRs) and cut wire (CW) resonator is designed to realize electromagnetically induced transparency (EIT) effect in weak coupling region. Theoretical and simulated results show that by modulating the relative coupling distance between CW and SRR or mutual distance between SRR pair, the EIT-like phenomenon can be tailored. Furthermore, by introducing photosensitive silicon (Si) cell into the units of the dark mode resonator, actively optical control of the EIT-like effect is realized through increasing the dark mode damping rate. The present work provides an alternative method to design ultrasensitive sensors, filters and slow-light devices in the THz regime.