Nanohole arrays in metal films as optofluidic elements: progress and potential

Subwavelength holes in metal films exhibit coupled optical phenomena specific to structure geometry, incident light and properties of the near-surface medium. As optofluidic components, nanohole arrays in metal films present several opportunities. This review provides an overview of the unique optical characteristics of such arrays, with emphasis on their application in the micro and nano-fluidic environment. The majority of contributions in this area have focused on sensor applications, and the results of nanohole array based chemical and biomolecular sensors are reviewed here. Also relevant to on-chip analysis, various field and spectroscopic enhancements achieved with nanohole arrays are discussed. The general benefits and limitations of nanohole arrays for analytical applications are discussed in the context of existing tools. Beyond sensing, particle trapping and other potential optofluidic applications of nanohole arrays are discussed.