Abstract-Optical control of terahertz plasmon-induced transparency based on hybrid CsPbBr3 quantum dot metasurfaces

Yue Yang, Jining Li, Jie Li, Jin Huang, Qingyan Li, Yating Zhang, Haitao Dai, and Jianquan Yao

(a) Schematic illustration of the CsPbBr3 QDs based PIT structure. (b) Optical microscopy of the designed metasurface. (c) Design dimensions of a unit cell. (d) PL intensity and absorption spectrum of CsPbBr3 QDs. The inset shows the TEM image of the synthesized QDs. (e) Measured transmission spectra of the PIT structure with and without spin-coating PEDOT: PSS/ CsPbBr3 QDs.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-28-16-24047

Incorporating photosensitive material into structured metamaterials explores opportunities for dynamical operation across the terahertz functional devices, enabled by the efficient interaction between light and matter. In this work, the CsPbBr3 quantum dots are incorporated into the metasurfaces, realizing the active control of the plasmon-induced transparency. In the experiment, the normalized modulation depth of transparency effect is up to 74%. Rigorous numerical and theoretical simulations verify that the variation of dynamic physical process is associated with the charge storage capacity in the capacitive metasurface. An observed phase advance and group delay indicate the hybrid metasurface is useful for slow light application. In addition, the simple process provides a convenient way for the development of terahertz functional devices.

© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-All-optical switchable terahertz spin-photonic devices based on vanadium dioxide integrated metasurfaces

Jie Li, Jitao Li, Yating Zhang, Jining Li, Yue Yang, Hongliang Zhao, Chenglong Zheng, Jiahui Li, Jin Huang, Fuyu Li, Tingting Tang, Jianquan Yao,



https://www.sciencedirect.com/science/article/abs/pii/S0030401819310545

Metasurfaces based on Pancharatnam-Berry (P-B) phase can achieve strong spin angular momentum (SAM) to orbital angular momentum (OAM) conversion of light, which provides a new degree of freedom for light control and opens up a new way for the applications of metasurfaces in classical and quantum optics. With the development of high-speed, large-capacity information transmission and high-definition imaging, demand for multifunctional and tunable P-B phase metasurfaces increases. Here, we propose three switchable terahertz spin-photonic devices based on P-B phase metasurfaces for focusing (divergence), splitting and vortex generation of terahertz beams. Based on photo-induced insulator–metal phase transition of the vanadium dioxide (VO2) islands in reflective hybrid resonators, switching of the devices function between on- and off-state is obtained, and the amplitude switching efficiency is as high as 90%. This work provides new ideas for the design of active terahertz devices and facilitates the applications of terahertz spin-photonic devices based on metasurfaces.

Abstract-Frequency-switchable VO-based coding metasurfaces at the terahertz band

Jiahui Li, Yating Zhang, Jining Li, Jie Li, Yue Yang, Jin Huang, Chengqi Ma, Zhenzhen Ma, Zhang Zhang, Lanju Liang, Jianquan Yao



https://www.sciencedirect.com/science/article/abs/pii/S0030401819309204

In this paper, a frequency-switchable terahertz coding metasurface is demonstrated based on the phase transition of vanadium dioxide. Temperature excitation can initiate the insulator–metal transition of vanadium dioxide, thereby changing the resonant frequency of the metal-vanadium dioxide composite unit structure, then changing the operating frequency of the entire coding metasurfaces. We first design a 1-bit coding metasurface whose working frequency can be switched between 1 THz and 1.4 THz, with a switching bandwidth of 0.4 THz. Further more, a 2-bit coding metaurface is designed, whose working frequency can be switched between 1 THz and 1.5 THz with a switching bandwidth of 0.5 THz. This work provides a new design idea for the terahertz active coding metasurfaces which opens up a broad path for coding metasurface applications such as wireless terahertz communications.

Abstract-Low-loss polarization-maintaining THz photonic crystal fiber with a triple-hole core

Zhiqing Wu, Xiaoyan Zhou, Handing Xia, Zhaohua Shi, Jin Huang, Xiaodong Jiang, and Weidong Wu

https://www.osapublishing.org/ao/abstract.cfm?uri=ao-56-8-2288&origin=search

In this paper, we report a novel low-loss and polarization-maintaining terahertz (THz) photonic crystal fiber with a triple-hole unit inside the core. The properties of birefringence, effective material loss, confinement loss, bending loss, power fraction, dispersion, and single-mode condition are analyzed in detail by using the finite element methods. Simulation results show that high birefringence at a level of 10−2${10}^{-2}$ can be achieved by simply reducing the diameter of one air hole of the triple-hole core. And low effective material loss down to 30% of its bulk material loss can be achieved in our interested band around 3 THz, due to the high core porosity of the designed triple-hole core. Moreover, this design dramatically facilitates the fabrication process, because of the typical hexagonal structure with all circular air holes and avoiding the troublesome multiple sub-wavelength air holes in the core area. The results reveal that this proposal has potential for efficient THz transmission and other functional applications.

© 2017 Optical Society of America