Controllable transmissive-reflective multifunction terahertz metasurface by different polarization and operating frequencies

Abstract

Due to the limitations of frequency bands and control methods, it is difficult to achieve multi-functional integration and real-time regulation of full-space metasurfaces. In this paper, we proposed a switchable transmissive-reflective mode terahertz metasurface independently depending on the incident wave frequencies and polarizations. The unit cell consists of four metallic layers, which are separated by three silicon dioxide layers. When the x-polarized wave is incident along the ± z-axis, the meta-device achieves focusing function at 1.62 THz. When the y-polarized wave is incident along the ± z-axis, the structure generates the reflective two and four splitting beams at a frequency of 0.82 THz and realizes a focused beam with a topological charge of l=±1 at a frequency of 1.65 THz. The full wave simulation results are in good agreement with the theoretical calculation predictions. The metasurface provides a new idea for the control of terahertz devices, and has a broad application prospect in the field of terahertz systems.

Few-layer bifunctional metasurfaces enabling asymmetric and symmetric polarization-plane rotation at the subwavelength scale

“…Even single-layer unitary (i.e. nongradient) metasurfaces may yield conversion of an LP wave to a circularly polarized (CP) one 28,29 and diverse scenarios of polarization manipulation, in reflection mode [29][30][31] . Moreover, AT can be obtained by means of manipulation by CP waves in a single-layer unitary chiral metastructure, although a high forward-to-backward transmission contrast is not (easily) achievable [32][33][34] .…”

“…The interest in multifunctionality has been growing in recent years, since it offers unprecedented opportunities for unification and integration 27,29,[41][42][43][44][45][46][47][48] . According to this concept, two functionalities can be achieved in the different (often -closely spaced) frequency ranges or incidence-angle ranges, or even merged into one at a given angle and frequency 49 .…”