Actively tunable graphene ribbon based multi-band THz polarizer with a high extinction ratio

An electrically tunable surface plasmon resonance based graphene ribbon (GR) terahertz (THz) polarizer with an adjustable operating frequency, high extinction ratio, and low insertion loss is reported here, and is simple and fab-rication feasible. The proposed metasurface structure comprises a periodic array of graphene ribbons deposited on a quartz-silicon substrate. The operating frequency of the GR-polarizer can be tuned by varying the gap between GRs, GR pitch, GR width, and Fermi level in graphene. Beyond the available graphene-based polarizers, the pro-posed device exhibits a high extinction ratio (ER) of up to 75 dB with simultaneous insertion loss of & SIM;1.5 dB at the optimized frequency of 1.69 THz. In addition, an average ER of & SIM;30 dB with insertion loss of & SIM;2 dB in the broad frequency range of 0.8-2.5 THz is demonstrated. Such metastructure polarizing devices, enriched with the nontriv-ial functionalities of graphene, would open up a fertile platform for designing a range of integrated photonic com-ponents for useful applications in THz optoelectronics, biomedical engineering, and microfluidics. & COPY; 2023 Optica Publishing Group