Trapping and sorting of nanoparticles by bowtie-nanohole plasmonic tweezers

Abstract

Optical tweezers are a crucial tool for manipulating nanoscale objects, and have a wide range of applications in various fields. Bowtie-nanohole tweezers, a type of near-field optical tweezers, are particularly intriguing due to their strong near-field enhancement and unique characteristics. In this paper we provide a detailed discussion of the properties of bowtie-nanohole tweezers on trapping and sorting nanoparticles through theoretical and numerical results. It is discovered that the tweezers behave differently when trapping particles with varying refractive indices, leading to a discussion of sorting chiral particles. Moreover, the relative refractive index between the particles and the background solution greatly influences the trapping and sorting abilities of the tweezers. Finally, we investigate the performance of the tweezers at different wavelengths of incident light to determine the optimal working wavelength for trapping or sorting.