Plasmonic biosensor enabled by resonant quantum tunnelling
Jihye Lee, Yina Wu, Ivan Sinev, Mikhail Masharin, Sotirios Papadopoulos, Eduardo J. C. Dias, Lujun Wang, Ming Lun Tseng, Seunghwan Moon, Jong‐Souk Yeo, Lukáš Novotný, F. Javier Garcı́a de Abajo, Hatice Altug
Abstract
Metasurfaces provide an ideal platform for optical sensing because they produce strong light-field confinement and enhancement over extended regions that allow us to identify deep-subwavelength layers of organic and inorganic molecules. However, the requirement of using external light sources involves bulky equipment that hinders point-of-care applications. Here we introduce a plasmonic sensor with an embedded source of light provided by quantum tunnel junctions. An optically resonant, doubly periodic nanowire metasurface serves as a top contact for the junction and provides extremely uniform emission over large areas, amplified by plasmonic nanoantenna modes that simultaneously enhance the spectral and refractive index sensitivity. As a proof of concept, we demonstrate spatially resolved refractometric sensing of nanometre-thick polymer and biomolecule coatings. Our results open exciting prospects based on a disruptive platform for integrated electro-optical biosensors.