Analysis of solar harvesting and refractive index sensing of multifunctional metamaterial perfect absorbers based on Ag discs and B4C–VC cube films

Abstract

Conventional MPAs are mainly focused on achieving perfect absorption in a single direction, and this single function leads to their limitations in various practical applications. This paper proposes and investigates a multifunctional metamaterial perfect absorber (MFMPA) based on Ag discs and B₄C–VC cubic films. When light is incident from the top, gap mode, Fabry–Perot cavity resonance, and surface plasmon resonance (SPR) enable the MFMPA to achieve ultra-broadband perfect absorption of >90% with a bandwidth of up to 3122 nm (327–3449 nm). In the 750–1250 nm range, the propagating surface plasmon resonance (PSPR), localized surface plasmon resonance (LSPR), and gap modes contribute to the narrow-band perfect absorption of the MFMPA when the light source is incident from below. Our structure integrates multiple optical applications, including thermal radiation, solar energy capture, photothermal conversion, perfect cloaking, and nanoparticle detection, as demonstrated by its excellent broadband absorption performance, high sensitivity, and insensitivity to large angles and polarization.