Tunable multifunctional terahertz metasurface based on an indium antimonide medium.

Active adjustable terahertz multifunctional devices are crucial for the application of terahertz technology. In this paper, we propose a composite metasurface structure based on an indium antimonide metal octagonal pattern, which achieves different functional switching by controlling the phase state of indium antimonide material under different ambient temperatures. When indium antimonide exhibits in the dielectric state, by stacking and encoding the unit cell, the designed metasurface has the functions of two-beam splitting beam superposition, vortex beam and quarter beam superposition, and dual vortex beam superposition for circularly polarized and linearly polarized wave incidence. When indium antimonide appears in the metallic state, the encoding metasurface alters the modulation function of incident circularly polarized and linearly polarized terahertz waves. This terahertz metasurface provides a new approach for the design of multifunctional devices that can flexibly regulate terahertz wave metasurfaces.

Flexible manipulation terahertz beam based on an all-dielectric metasurface by utilizing addition and convolution algorithms.

The flexibly manipulated terahertz wave is currently a hot research topic. To address this challenge, we proposed an all-dielectric coding metasurface for shaping the terahertz wave including beam splitting, beam deflection, vortex beam generators, and a vortex beam and multi-beam splitting combination by combining addition with the convolution theorem. This work represents what we believe to be a new method of combining terahertz wave regulation with digital signal processing and opens up the versatile design ideas of multifunctional metadevices.

Reconfigurable three multi-mode terahertz metasurface.

We designed a three reconfigurable multi-mode terahertz metasurface based on a concentric elliptical ring structure. The proposed unit cell is a concentric elliptical ring composed of copper, vanadium oxide and photosensitive silicon from the inside ring to the outside ring. The conductivity of photosensitive silicon and vanadium oxide can be adjusted by changing the external operating temperature and pump light intensity. The same unit cell can reconstruct three kinds of states with different properties, and they have completely different transmission characteristics in various terahertz bands. By encoding the arrangement, through changing external stimulus and operating frequencies, the reconfigurable terahertz metasurface can achieve multiple functions including terahertz focusing with adjustable focal length, vortex beam with different topological charge, and near-field imaging with different patterns. It provides what we believe to be a new idea for the field of information security and the design of multifunctional and multifrequency terahertz devices.