Dynamic control of reflective chiral terahertz metasurface with a new application developing in full grayscale near field imaging

Dynamic phase assembled terahertz metalens for reversible conversion between linear polarization and arbitrary circular polarization

“…By arranging different structure units according to a certain phase distribution, the metalens can realize not only the focusing function similar to the traditional convex lens, but also the polarization conversion function 22−26 . In general, THz metalens widely uses all-dielectric silicon (Si) material with transmission structure so as to meet the practical applications 27 . If THz metalens can also achieve CP conversion, they can replace both traditional CPL and focus lens, and are used in advanced THz camera, further reducing the camera volume.…”

Diatomic terahertz metasurfaces for arbitrary-to-circular polarization conversion

“…Circular dichroism (CD), that is, the differential absorption effect of left-handed circularly polarized (LCP) waves and right-handed circularly polarized (RCP) waves, 11 in other words, exclusively one kind of circular polarization mode can be transmitted and converted to its handedness-flipped state, while other orthogonal circular polarization states are fully blocked. 12 In fact, the generation of chirality can be regarded as a polarization conversion in a specific case. However, the responses of existing chiral nano-structures are generally weak, with many limitations in practical applications.…”

Graphene-based terahertz bias-driven negative-conductivity metasurface

“…Therefore, metasurfaces are typically combined with other materials to form a hybrid metasurface for achieving the exible control of THz waves by applying external control conditions to the device. [15][16][17][18] Graphene is a single-atom form of carbon with a sp 2hybridization honeycomb crystal plane. Since its rst successful preparation in 2004, 19 monolayer graphene has shown high carrier mobility, broadband at optical response, tunable bandgaps, high electronic and optical conductivities, and many other unique electrical and optical properties, thus garnering extensive research attention.…”