Figure 1

Optical absorption spectra for the different metallic NPs studied in this work: (a) Pt NPs embedded in silica; (b) Pt NPs in sapphire; (c) Au NPs in sapphire; (d) Ag NPs in sapphire. Inset graphs in (c) and (d) show the size distribution used to simulate the optical absorption according to Mie calculations for Au and Ag NPs in sapphire.