Arrays of Bowtie Plasmonic Nanoantennas for Field Enhancement in MOEMS

Abstract

Many micro(nano)optoelectromechanical systems (MOEMS, NOEMS) require optical (generally, electromagnetic) field localization and concentration. These include for instance photocatalytic microreactors and labs on a chip, where it is necessary to localize optical energy into a fluidic channel. Other examples are chemical and biological sensors. Plasmonics on the other hand ensures field localization down to subwavelength volumes where evanescent fields can be tailored to the shape of minuscule channels in MOEMS and NOEMS. In this work we present a possible approach to the enhancement of optical fields in MOEMS and NOEMS systems where a linear array of plasmonic bowtie structures is used to concentrate the optical field into a dielectric channel. We perform our numerical simulations using the finite element method to analyze field distributions that can be achieved by the use of the bowtie antenna and the possibility to tailor these fields. We also analyze the influence of the shape of the coupled tips of bowties to the field distribution and frequency dispersion. We conclude that arrays of plasmonic bowties could be a promising candidate for optically assisted micro and nanofluidics.