Optical biosensor in the mid-infrared frequency range based on Weyl semimetals

Abstract We present an optical biosensor that combines several layers of Weyl semimetal with a finite one-dimensional photonic crystal to detect various analytes in the mid-infrared frequency range. As a new type of topological material, Weyl semimetals can naturally support surface waves in the infrared spectrum. Our results demonstrate that excitation of the Tamm surface plasmon polaritons in the proposed structure results in significantly high sensing performance. In particular, we show that a biosensor comprising two or three layers of Weyl semimetals, separated by dielectric layers, can simultaneously improve all relevant sensing parameters. Additionally, we analyze how the alignment of the axial vectors of the Weyl semimetal layers affects these sensing parameters. Our findings reveal that altering the direction of the axial vectors can profoundly change the biosensor’s performance. Based on these insights, we conclude that biosensors utilizing Weyl semimetals have the potential to serve as a foundation for the development of high-performance biosensors operating in the mid-infrared frequency range.