Terahertz polarization sensing, chirality enhancement, and specific binding based on metasurface sensors for biochemical detection: a review [Invited]

Specific and highly-sensitive biochemical detection technology is particularly important in global epidemics and has critical applications in life science, medical diagnosis, and pharmaceutics. As a newly developed technology, the THz metamaterial-based sensing method is a promising technique for extremely sensitive biomolecular detection. However, due to the significant resonant peaks generated by THz metamaterials, the characteristic absorption peaks of the analyte are usually masked, making it difficult to distinguish enantiomers and specifically identify target biomolecules. Recently, new ways to overcome this limitation have become possible thanks to the emergence of chiral metasurfaces and the polarization sensing method. Additionally, functionalized metasurfaces modified by antibodies or other nanomaterials are also expected to achieve specific sensing with high sensitivity. In this review, we summarize the main advances in THz metamaterials-based sensing from a historical perspective as well as application in chiral recognition and specific detection. Specifically, we introduce the basic theory and key technology of THz polarization spectrum and chiral sensing for biochemical detection, and immune sensing based on biomolecular interaction is also discussed. We mainly focus on chiral recognition and specific sensing using THz metasurface sensors to cover the most recent advances in the topic, which is expected to break through the limitations of traditional THz absorption spectroscopy and chiral spectroscopy in the visible-infrared band and develop into an irreplaceable method for the characterization of biochemical substances.