A nanoscale gap aperture has been used as a fundamental tool for diverse applications. In this paper, we investigate the effect of nanogap aperture parameters on optical sensors, primarily based on surface plasmon resonance. A simple 2-D model was used for DNA immobilization and hybridization, in which nanogap enables light-matter colocalization to amplify detection signatures, thereby enhancing performance characteristics. Interestingly, the optimum gap geometry that produces maximum light-matter overlap and the largest resonance shift was not associated with the smallest gap size. Highest sensitivity was observed to correlate with negative resonance shift due to increased damping as well as the excitation of higher order surface plasmon polariton modes. Zero-shift nanogap was also discussed. The results suggest that careful design of nanogap apertures should be carried out to make the most of what they can achieve.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics