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-Refractive aspherical lens for terahertz imaging

Weifan Li, Feng Qi, Yelong Wang, Pengxiang Liu, Zhaoyang Liu


https://www.sciencedirect.com/science/article/abs/pii/S0030401818308605

In this paper, we introduce two convex-plano lenses for terahertz (THz) imaging applications. The first lens is determined to use an aspherical surface and compared with a similar spherical lens that has the same diameter, thickness, and back focal length. We demonstrate the superiority of aspherical surface by electromagnetic simulations and focal plane scanning experiments. The second lens has a relatively shorter focal length and has excellent focusing capability. By comparing with other two previous studies, we estimate that this lens may achieve high-resolution in THz imaging applications.