Designs of metareflectors based on nanodisk and annular hole arrays with polarization independence, switching, and broad bandwidth characteristics

• Published in: Optical materials express Vol. 11; no. 10; p. 3577
• Main Authors: Xu, Xiaocan, Lin, Yu-Sheng, Fang, Rongpeng, Yang, Bo-Ru
• Format: Journal Article
• Language: English
• Published: Washington Optical Society of America 01.10.2021
• Subjects: Active mirrors; Aluminum; Augmented reality; Nanostructure; Optical communication; Resonance; Silicon substrates; Switches; Switching; Tuning; Virtual reality
• ISSN: 2159-3930; 2159-3930
• DOI: 10.1364/OME.437980

We propose two tunable metareflectors (MRs) composed of a suspending nanodisk and an annular hole on silicon (Si) substrate with aluminum (Al) mirrors atop. They are denoted as MR-1 and MR-2 for the former and latter, respectively. The proposed MRs exhibit high-efficient cyan-magenta-yellow (CMY) color filtering, and ultrabroad tuning range characteristics. The electromagnetic energy of the resonant wavelength is confined within the suspending nanostructure and bottom Al mirror and then performed a perfect absorption. By changing the height between suspending nanostructure and the bottom Al mirror, MRs exhibit active tuning and single-/dual-resonance switching characteristics spanning the entire visible spectra range. Furthermore, the resonant wavelengths of MRs are sensitive to the surrounding ambient media, which are red-shifted and modulated from single- to dual-resonance by changing the environmental refraction index. The corresponding sensitivities are 500 nm/RIU and 360 nm/RIU for MR-1, 289 nm/RIU and 270 nm/RIU for MR-2, respectively. These results provide an effective strategy for use in high-resolution displays, high-sensitive sensors, optical switches, optical communications, and flexible virtual reality (VR)/augmented reality (AR) applications.