Graphene nanophotonic sensors

Graphene is known to possess a host of remarkable properties such as a zero bandgap at its Dirac point, broadband saturable optical absorption, ballistic carrier transport at room temperature, as well as extremely high stiffness and thermal conductivity. This has in turn made it a material of interest for many applications, ranging from fundamental physics studies to electronic devices. From a photonics perspective, graphene's ability to support surface plasmon-polaritons with extremely small mode volumes in the infrared spectral regime and beyond renders it an ideal platform for strongly enhanced light–matter interactions at deeply subwavelength size scales. Together with its large bandwidth of operation, as well as intrinsic chemical stability and affinity to organic molecules, graphene serves as a natural candidate for numerous optics-based sensing applications. This article reviews recent works that highlight the various advantages of graphene in an optical sensing context. Specifically, it focuses on how the passive functionalization of graphene can improve the performance of existing optical sensors, and how its use as an active signal transduction element could lead to various novel or hybrid devices that extend the functionalities of traditional sensors.