Study on the enhancement mechanism of terahertz molecular fingerprint sensing

•Design an all-dielectric structure based on light polarization and angle multiplexing.•Our solution yields significantly enhanced trace (0.5 μm) molecular fingerprints.•Our method is biospecific, which opens up new opportunities for label-free biosensing.•Our proposed scheme without the need for a complex light source system. THz-time domain spectroscopy is an effective method of label-free molecular detection, but it is limited by the size of the measured samples. Traditional detection approaches will have to overcome challenges when the analyte are in trace amounts. Here, we propose an enhanced mechanism for terahertz molecular fingerprint sensing, involving an all-dielectric metasurface. Based on incident wave angle scanning under light polarization, the broadband light–matter interaction is effectively enhanced, significantly improving the fingerprint signal of the molecule to be detected. The results demonstrate a new method for trace molecular detection in the terahertz region and large-scale molecular screening.