Metasurfaces, two-dimensional (2D) or planar versions of metamaterials exhibit properties that are not typically found in natural materials. As they are flat, these materials can typically be produced using widely known fabrication processes and may help to control the propagation of electromagnetic waves in various devices.
Most metasurfaces follow the rules outlined by the so-called Lorentz reciprocity theorem, which basically means that they exhibit characteristics that are symmetrically aligned to the direction of electromagnetic wave propagation. Non-reciprocal metasurfaces are an emerging class of metasurfaces that do not obey the Lorentz reciprocity theorem.
In contrast with conventional metasurfaces, non-reciprocal metasurfaces could encode optical functions on waves that are propagating both forward and backward. This key characteristic could make them particularly promising for the development of several technologies, including non-reciprocal antennas or protective structures known as radomes, which are designed to preserve the operation of radar antennas or wireless communication systems.
Researchers at the University of Electronic Science and Technology of China and Massachusetts Institute of Technology (MIT) recently developed a new non-reciprocal and magnetic metasurface that could provide be used to create new devices with various non-reciprocal functionalities. This metasurface, introduced in Nature Electronics, was created using a series of self-biased magnetic meta-atoms made of lanthanum(La)-doped barium hexaferrite (BaFe12O19).
To read more, click here.