Electromechanically reconfigurable plasmonic nanoslits for efficient nano-opto-electro-mechanical tuning

• Published in: Materials today physics Vol. 42; p. 101369
• Main Authors: Yun, Hyeong Seok, Liu, Xiu, Salihoglu, Hakan, Li, Zhuo, Shen, Sheng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2024
• Subjects: Active metamaterial; Nano-opto-electro-mechanical system (NOEMS); Nanogap; Plasmonics; Nano-opto-electro-mechanical system (NOEMS); Active metamaterial; Plasmonics; Nanogap
• ISSN: 2542-5293; 2542-5293
• DOI: 10.1016/j.mtphys.2024.101369

Plasmonic metamaterials with strong localized surface plasmon resonances (LSPRs) have been improved by incorporating a nano-opto-electro-mechanical system (NOEMS) for tunable optical and electrical responses. However, conventional NOEMS devices suffer from the inefficient free-space coupling due to the limited design of reconfigurable antennas and the low optical tunability due to electrostatic pull-in of moving parts. In this paper, we propose efficient mid-infrared plasmonic nanoslits with variable nanometer-sized gaps giving rise to broad optical tunability. Our finite element method (FEM) analysis shows that by applying a voltage bias to asymmetric nanoslits supported on dielectric pillars, the gap width can be increased by more than 60 nm from an initial 1 nm. The large change in gap width results in a significant spectral shift in reflectance, while maintaining strong free-space coupling and a constant full width at half maximum (FWHM). We also analyze the effect of geometrical parameters on the nanometer-sized gap width and optical responses. Our nanoslits with simple geometry resulting in efficient optical coupling show promise for improving active metasurfaces and electromechanically tunable plasmonic devices.