A terahertz metasurface biosensor based on electromagnetically induced transparency for fingerprint trace detection

Abstract

A highly sensitive and accurate detection is long-awaited for terahertz (THz) metasurface biosensors through a comprehensive multi-modal sensing and fingerprint trace enhancement. Herein, we present a polarization-insensitive THz biosensor with a sensitivity up to 411.6 GHz per RIU (4-μm-thickness analyte) based on an electromagnetically induced transparency (EIT) metasurface. Moreover, the carcinoembryonic antigen is accurately identified through a multi-modal resonance, achieving a limit of detection (LOD) of 2.5 ng, and a qualitative and quantitative investigation into an enhanced fingerprint detection for extremely thin analytes is also conducted, which reveals that the transparency peak is exceptionally sensitive to the fingerprint vibration of substances through its amplitude variation. Thus, the proposed THz EIT metasurface achieves a highly sensitive sensing and fingerprint detection, which is beneficial for qualitative and quantitative biological identifications in the fields of biomedicine, food safety and drug detection to some extent.