Engineering Plasmonic Lattice Structures for Lab-on-Chip Sensing Platforms

Abstract

The study of plasmonics has increased in the past decades due to the benefits they offer to a wide range of application areas including optics, point-of-care sensing, spectroscopy, imaging, etc. The fabrication of plasmonic devices has relied on sub-micron to nanoscale fabrication techniques that are typically low throughput, and often result in transducers that are challenging to integrate with other lab-on-chip components. Methods based on a combination of bottom-up self-assembly and top-down nanosphere lithography based provided solutions to these fabrication challenges. This paper will discuss the design and fabrication of nanosphere-based plasmonic lattices that directly utilize nanosphere deposition to create resonant plasmonic transducers capable of resonant enhancement of quantum dot and fluorescent labels with visible-spectrum emission. Parametric simulations of critical plasmonic lattice dimensions using finite-difference time-domain (FDTD) software will be presented to offer insight into design optimization for maximum emission enhancement for a given range of commercially-available nanobeads. Fabrication of the sub-micron lattice using nanobeads sized in the 100-500 nm range in an evaporative deposition process will be described, along with an evaluation of variations in ‘as-drawn’ and fabricated lattice dimensions. Characterization results indicating 10-fold+ enhancement of photonic emission from labeled analyte in suspension will be provided. Figure 1