Metamaterial-based label-free optical biosensing

Metamaterials have drawn extensive attention for their fine regulation of electromagnetic waves at subwavelength scales. They have abundant electromagnetic modes, and support highly confined and enhanced electromagnetic fields on the surface which are highly sensitive to the surrounding dielectric environment, so they can be used in label-free optical biosensing. Compared with traditional optical biosensors, metamaterial biosensors have many advantages, such as miniaturization, integration, high sensitivity and multi-function customization. The recent progress of metamaterial biosensors in visible light and near infrared, middle infrared, and terahertz spectrums was summarized in this paper, including refractive index biosensing, surface-enhanced Raman scattering, surface-enhanced infrared absorption, and terahertz biosensing