Photonic gas sensors exploiting directly the optical properties of hybrid carbon nanotube localized surface plasmon structures

摘要

An all-optical gas sensor based on carbon nanotubes on a plasmonic structured fibre provides sensitive detection of carbon dioxide gas. Thomas Allsop and co-workers say that the approach offers initial detection limits as low as 150 parts per million at a pressure of one atmosphere. The device consists of a milled optical fibre whose flat surface is coated with thin layers of germanium, silicon dioxide and platinum that are patterned by ultraviolet light to form a surface relief grating. This grating features a plasmonic resonance that is sensitive to changes in the optical properties of the carbon nanotubes on its surface induced by exposure to carbon dioxide. The presence of carbon dioxide manifests itself as a small shift in the plasmon resonance wavelength, which increases with increasing carbon dioxide concentration.