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-Optimization for vertically scanning terahertz attenuated total reflection imaging

Hongxiang Liu, Yuye Wang, Degang Xu, Zhinan Jiang, Jining Li, Limin Wu, Chao Yan, Longhuang Tang, Yixin He, Dexian Yan, Xin Ding, Hua Feng, and Jianquan Yao

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-16-20744

Terahertz attenuated total reflection imaging has been used to develop preliminary applications without any in-depth analysis of the nature of present systems. Based on our proposed vertically scanning imaging system, an analysis of optimum prism design and polarization selection for error reduction is presented theoretically and experimentally, showing good agreement. By taking the secondary reflection inside the prism and the prism deflection into consideration, p-polarized terahertz waves are recommended for prisms with a base angle below 31°, leading to minimum error. This work will contribute to the development of more practical application of terahertz attenuated total reflection scanning imaging in various fields with enhanced performance.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Active KTaO3 hybrid terahertz metamaterial

• Liang Wu, 
• Jinglong Liu, 
• Hui Li, 
• Chunfeng Ding, 
• Ningning Xu, 
• Xiaolei Zhao, 
• Zongcheng Xu, 
• Quan Sheng, 
• Jianquan Yao, 
• Jining Li, 
• Xin Ding & 
• Weili Zhang

https://www.nature.com/articles/s41598-017-05529-0

The dielectric properties of an active KTaO3 hybrid metamaterial structure and its tunability under external electric fields are investigated at room temperature by means of terahertz time-domain spectroscopy. Application of the electric field leads to an appreciable tuning of the dielectric loss, which is up to 17%. Meanwhile, the refractive index also changes appreciably. These findings are attributed to the internal space charge field in the crystal caused by the excited free carriers.

Abstract-Mechanically tunable terahertz metamaterials

Jining Li^1,2, Charan M. Shah³, Withawat Withayachumnankul¹, Benjamin S.-Y. Ung¹, Arnan Mitchell³, Sharath Sriram³, Madhu Bhaskaran³, Shengjiang Chang², and Derek Abbott¹

¹School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, SA 5005, Australia
²Institute of Modern Optics, Nankai University, Tianjin 300071, China
³Functional Materials and Microsystems Research Group, RMIT University, Melbourne, VIC 3001, Australia                        

http://apl.aip.org/resource/1/applab/v102/i12/p121101_s1?isAuthorized=no

Electromagnetic device design and flexible electronics fabrication are combined to demonstrate mechanically tunable metamaterials operating at terahertz frequencies. Each metamaterial comprises a planar array of resonators on a highly elastic polydimethylsiloxane substrate. The resonance of the metamaterials is controllable through substrate deformation. Applying a stretching force to the substrate changes the inter-cell capacitance and hence the resonance frequency of the resonators. In the experiment, greater than 8% of the tuning range is achieved with good repeatability over several stretching-relaxing cycles. This study promises applications in remote strain sensing and other controllable metamaterial-based devices.

© 2013 American Institute of Physics