Abstract-Enhancing terahertz molecular fingerprint detection by a dielectric metagrating

Jinfeng Zhu, Shan Jiang, Yinong Xie, Fajun Li, Lianghui Du, Kun Meng, Liguo Zhu, and Jun Zhou

https://www.osapublishing.org/ol/abstract.cfm?URI=ol-45-8-2335

Terahertz (THz) sensing of molecular fingerprint enables wide applications in biomedicine and security detection. Conventional detection approaches face big barriers in trace analysis of analyte due to the difficulties of enhancing the broadband molecular absorption. In order to achieve strong broadband wave–matter interaction for the analyte, we propose a method based on THz wave angular scanning on a dielectric metagrating. In virtue of the guided-mode resonance, one can strengthen the local electric field in various trace-amount analytes by tuning the polarization and incident angle, which leads to significant enhancement on the broadband signal of molecular fingerprint. The study paves the way for more applications of THz trace-amount detection.

© 2020 Optical Society of America

Abstract-Subdiffraction focusing of total electric fields of terahertz wave

Mengyu Yang, Desheng Ruan, Lianghui Du, Chunyan Qin, Zeyu Li, Cuiping Lin, Gang Chen, Zhong Quan Wen,



https://www.sciencedirect.com/science/article/abs/pii/S0030401819309307

Terahertz lens is an essential component in terahertz application. We propose a focusing of total electric fields planar lens based on super-oscillation. This planar lens is designed for a wavelength ($\lambda$) of 118.$8\mathrm{\mu }\mathrm{m}$ with a radius of 160$\lambda$, a focal length of 210 $\lambda$ and a numerical aperture of 0.606. Our experiment demonstrates a subdiffraction and subwavelength focusing of total electric fields. The full width at half-maximum of the focal spot is 0.67 $\lambda$, which is smaller than the diffraction limit of 0.825$\lambda$. The results shows that it has powerful application for terahertz imaging, especially in the fields of biomedical science.

Abstract-All-dielectric metalens for terahertz wave imaging

Xue Jiang, Hao Chen, Zeyu Li, Hongkuan Yuan, Luyao Cao, Zhenfei Luo, Kun Zhang, Zhihai Zhang, Zhongquan Wen, Li-guo Zhu, Xun Zhou, Gaofeng Liang, Desheng Ruan, Lianghui Du, Lingfang Wang, Gang Chen,

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-11-14132

Terahertz wave imaging offers promising properties for non-destructive testing applications in the areas of homeland security, medicine, and industrial inspection. However, conventional optical lenses are heavy and bulky and difficult to integrate. An all-dielectric metasurface provides an attractive way to realize a planar lens of light weight that is ultrathin and offers ease of integration. Terahertz lenses based on various metasurfaces have been studied, especially for the application of wave focusing, while there are few experimental demonstrations of terahertz wave imaging lenses based on an all-dielectric metasurface. In the present work, we propose a metalens based on an all-dielectric metasurface with a sub-wavelength unit size of 0.39λ for terahertz wave imaging and experimentally demonstrate its performance in focusing and imaging. A large numerical aperture metalens was fabricated with a focal length of 300λ, radius of 300λ, and numerical aperture of 0.707. The experimental results show that the lens can focus THz waves with an incident angle up to 48°. More importantly, clear terahertz wave images of different objects were obtained for both different cases of forward- and inverse-incident directions, which demonstrate the reversibility of the metalens for imaging. Such a metalens provides a way for realization of all-planar-lens THz imaging system, and might find application in terahertz wave imaging, information processing, microscopy, and others.

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