Temperature Tunable Multiple Ultraviolet to near-Infrared Perfect Absorption as Highly Sensitive Metamaterial Biosensor

Realizing tunable multi-band perfect absorption from ultraviolet to near-infrared range in nanophotonics and metamaterials is extremely significant for solar energy harvesting and optical sensors. Here, five narrowband and broadband perfect absorbers (PA) are simultaneously achieved in a simple 3D metamaterial consisting of aluminum (Al) standing U-shaped split-ring resonators (SUSRRs) on SiO ₂ /Al layer, which stems from the plasmonic hybridization between three high-order surface plasmon polarization (SPPs) and multiple localized surface plasmon (LSPs) localized both within the individual SUSRR as well as within the dielectric layer underneath the SUSRR. These penta-band perfect absorption peaks can be tuned by varying the temperature of the sealed ethanol with a temperature tuning performance of 0.331 nm/°C. Due to the two narrow perfect absorption at 473 nm and 157 nm being sensitive to the surroundings, our proposed Al SUSRR array as a high-sensitivity biosensor displays the ultra-large figure of merit ( FoM *) of 3.0×10 ⁴ and 1.55×10 ⁴ , which could be applied to gas sensing and the detection of the sub-nanometer thickness of analyte film.