GRAPHENE BASED METASURFACE POLARIZATION CONVERTER

Abstract

Metasurface refers to a flat interface that has been artificially structured to en able precise and controlled manipulation of electromagnetic waves. It is made up of tiny elements that are arranged periodically or non-periodically to achieve the desired optical properties. The use of metasurfaces has significantly transformed the field of electromagnetic wave control and created new possibilities in photonics, optics, and communication technology.One of the primary applications of metasurfaces is in controlling electromagnetic wave polarization. Polarization is a characteristic of elec tromagnetic waves that describes the orientation of their electric field. By regulating the polarization of a wave, it becomes possible to manipulate its direction of propa gation, intensity, and phase. Polarizers, which transmit or reflect waves of a specific polarization state, can be designed using metasurfaces. This dissertation proposes a unique design for a reflecting type polarizer capable of linear to cross conversion in the THz domain. The polarizer unitcell comprises a substrate on which thin graphene is created, while a thin gold sheet serves as the ground plane. The converter displays a linear-cross conversion with a minimum PCR of 90% within the 1.86 to 2.92 THz frequency range.The main benefit of this design is that the metasurface’s performance remains stable when electromagnetic waves strike it from oblique angles with both transverse electric (TE) and transverse magnetic (TM) incidence angles up to 45. This feature is crucial for practical applications, where the incidence angle of electromagnetic waves may vary based on the source or the environment. The potential impact of using metasurfaces in communication technology is vast, as it has the capacity to improve transmission efficiency, reduce signal interference, and increase bandwidth by creating devices with diverse functionalities