Fig. 4

Scattering spectra for varying n₂ = 1.5, 2.0, and 2.5 of structure A (a–c) and structure C (d–f) respectively. Light is incident normally from air (denoted as black lines) and substrates (denoted as red lines). The blue lines show the scattering spectra of which the Au NPs are surrounded by infinite dielectric mediums with effective refractive indices