Recent progress in terahertz biosensors based on artificial electromagnetic subwavelength structure

Terahertz (THz) sensing technology attract tremendous interest in the past few decades for its unique applications in various fields, including wireless communications, spectroscopy, imaging, and noninvasive detection. In parallel to this, metamaterials and two-dimensional (2D) materials exhibit unusual optical and electrical properties, which has prompted great attention and significant advances in THz biosensing. This work reviews fundamentals and the recent state-of-art achievements in the field of THz biosensors based on artificial electromagnetic subwavelength structure. Firstly, the sensing principle is briefly introduced. Subsequently, we focus on the development of different materials and structures, including metallic materials, nonmetallic materials, hybrid materials, and prism coupled structures. In addition, we introduce the fabrication of THz subwavelength structure sensors and microfluidic platform, and show the applications of THz biosensors in recent years. Lastly, we discuss the challenges and opportunities and present our prospects for future development.