The sensing of chiral molecules is important for chemical, pharmaceutical, and medical applications. The fast and accurate testing of small quantities of analyte by optical means is desirable, in particular for lab-on-a-chip technologies. Different nanostructures have been proposed for enhancing the molecular circular dichroism (CD) in their near fields, yet not all structures and near fields serve this purpose equally well. We will present the design guidelines that lead to nanostructures that enhance the CD signal of molecular solutions, use these guidelines for optimizing arrays of silicon disks, and demonstrate a more than tenfold increase in sensitivity.
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