A Non-Volatile Tunable Terahertz Metamaterial Absorber Using Graphene Floating Gate

Based on the graphene floating gate, a tunable terahertz metamaterial absorber is proposed. Compared with the traditional graphene–dielectric–metal absorber, our absorber has the property of being non-volatile and capacity for anti-interference. Using the finite element method, the paper investigates the absorption spectra, the electric field energy distribution, the tunability and the physical mechanism. In addition, we also analyse the influence of geometry, polarization and incident angles on the absorption. Simulation results show that the bandwidth of the absorption above 90% can reach up to 2.597 THz at the center frequency of 3.970 THz, and the maximum absorption can be tuned continuously from 14.405% to 99.864% by controlling the Fermi level from 0 eV to 0.8 eV. Meanwhile, the proposed absorber has the advantages of polarization insensitivity and a wide angle, and has potential applications in imaging, sensing and photoelectric detection.

Characterization of a Vertical-Cavity Enhanced Detector for Narrowband Detection in the Mid-Infrared

In this work we present the experimental characterization of a vertical-cavity enhanced resonant detector (VERD) optimized for detection in the mid-infrared. We demonstrate that the VERD shows a 7.1 times higher absorption and responsivity at 4.26 µm compared to a bare metal absorber. As such this design can be easily optimized and integrated to specifically enhance the absorption around the design wavelength.