Simultaneous Quantification and Identification of Protein by Metamaterial Perfect Absorber

The metamaterial perfect absorber (MPA) has become a promising biosensor platform due to its surface-enhanced infrared absorption (SEIRA) effect. In this paper, we demonstrate a polarization-insensitive MPA for ultra-sensitive detection of trace biomolecules. Here, the sensing of MPA platform depends on the absorption intensity and resonance shift. Among them, the absorption intensity provides molecular vibration information that can be used to identify biomolecular species. Resonance shift can be used to determine the concentration of biomolecules because the binding of molecules will cause a change in the effective refractive index near the optical antenna. These two sensing information enable the MPA platform to simultaneously achieve high sensitivity and high specificity detection of biomolecules.