Durmaz, H.Erturan, A.M.2023-12-092023-12-09202397813941670749781394166220https://doi.org/10.1002/9781394167074.ch3https://hdl.handle.net/20.500.13091/4877Metamaterials are manufactured materials that do not occur naturally in nature and have unique features, such as a negative refractive index, exceptional transmission, and a negative Doppler effect. These features enable them for use in stealth technology, super-lenses, perfect absorption, ultrasonic sensors, etc. With its capacity to accomplish complete absorption of incoming electromagnetic radiation with subwavelength features, perfect absorbers based on these material groups have grabbed the interest of many researchers. Here, we present the fundamental theory behind the perfect absorption mechanism in metamaterials having sub-wavelength structures via interference, transmission line, and impedance matching theories. We provide an overview of metamaterial perfect absorbers with 100% absorptivity. In addition, we discuss biosensors based on metamaterial perfect absorbers, such as surface-enhanced infrared spectroscopy (SEIRA) and refractive index sensors. Finally, we conclude the book chapter by giving our opinions on what we think will contribute to the development of metamaterial perfect absorbers. © 2023 Scrivener Publishing LLC. All rights reserved.eninfo:eu-repo/semantics/closedAccessMetamaterial biosensorsMetamaterial perfect absorbersMetamaterialsPerfect absorptionPlasmonic biosensorsPlasmonicsRefractive index sensorsSEIRABook Part10.1002/9781394167074.ch32-s2.0-85175121139