Figure 1. Characteristics of the plasmonic nanoparticles.

(a) Sketch of the investigated plasmonic nanoparticles. (b) Absorption spectra in water for the three investigated nanoparticle types show that AuNPs with diameters of 80 nm and 150 nm exhibit resonances in the visible region (400–700 nm), whereas the AuNSs (diameter 150 nm) have their resonance peak in the near infrared region (700–1100 nm).