Optical Trapping, Biosensing, and Spectroscopy in a Single Plasmonic Platform

Abstract

We propose plasmonic platform that can enable optical trapping, spectroscopy and biosensing, all in the same platform. The system is based on periodic arrays of gold nanopillars fabricated on a supporting gold layer. The proposed platform is highly desirable for biosensing applications since it supports highly refractive index sensitivities as large as 675 nm/RIU which. The spectrally sharp resonances provides large figure of merits as large as 112.5. As the nanopillar array supports large near-field intensities accessible to the biomolecules in the sample around the platform, as large as 10.000 times, the proposed structure can be used for surface enhanced spectroscopy applications. The pillar array also supports plasmonic hot spots with high near-field intensity gradient leading to large gradient forces, 350 pN/W/μm² which is needed for optical trapping applications.