Design of a Planar Metamaterial Absorber Capable of Optical Sensing from 500 to 3160 nm

In this study, a planar multilayer metamaterial absorber capable of optical sensing across an ultra-broadband spectrum was designed and numerically analyzed using the finite element method implemented in the simulation software COMSOL Multiphysics (V6.0).The absorber consists of alternating metal-dielectric layers, with SiO 2 serving as the scattering medium to enhance electromagnetic coupling and impedance matching.A six-layer planar structure composed of V, Ge, Bi, and Co was first developed, achieving an average absorptivity of 94.56% within the 500-3160 nm wavelength range, though a slight absorption dip was observed between 400-500 nm.By introducing additional SiO 2 and Co layers to form an eight-layer configuration, the absorption bandwidth was broadened to 400-3700 nm with an average absorptivity of 93.69%.Furthermore, replacing Co with Ti extended the spectral response to 400-4000 nm, demonstrating enhanced optical adaptability.These findings indicate a design trade-off between absorption efficiency and bandwidth coverage, offering valuable insights for the development of high-performance optoelectronic and sensing devices based on planar metamaterial architectures.