Terahertz polarizer based on tunable surface plasmon in graphene nanoribbon
Dip Sarker, Partha Pratim Nakti, Md Ishfak Tahmid, M. Asaduz Zaman Mamun, Ahmed Zubair
Abstract
Tunable surface plasmon resonance-based graphene nanoribbon (GNR) terahertz (THz) polarizers with adjustable operating frequency are proposed in this work. While conventional THz polarizers lack robustness and tunability, recently reported graphene-based metastructure polarizers have complex fabrication processes and comparatively smaller extinction ratios (ERs). A comprehensive study using finite-difference time-domain (FDTD) simulation technique reveals high ER, broad tunability, near-perfect degree of polarization (DOP), and low insertion loss for our proposed single and double stage GNR polarizers. The operating frequency of these narrow band polarizers can be tuned by varying GNR width, GNR pitch, chemical potential, and substrate material. Our optimized THz polarizer has an ER of 30 dB which is comparable to the commercially available THz polarizers. The maximum insertion losses within the tunable frequency range were found to be 0.24 dB and 1.87 dB for single and double stage GNR polarizers, respectively, which are substantially low. We compared the performance of the proposed structures with recently demonstrated graphene-based metastructure polarizers. The polarizers are promising for the design of photonic devices, integrated photonic circuits, and optoelectronic systems.