ABSTRACT
Embedded NP production by man has a history much longer than many might expect. e famous Lycurgus Cup, a Roman relic from the fourth century AD now housed in the British Museum, changes in color from opaque green to translucent red as the illumination source changes from re ected to transmitted, respectively. is intriguing behavior, shown in the photographs of Figure 23.2a and b, stems from the absorption and the scattering of light by embedded Au and Ag NPs present in the glass (Maier and Atwater 2005; British Museum 2008). Speci cally, the shorter wavelengths (green light) are readily scattered while the longer wavelengths (red light) are transmitted (Atwater 2007). Another early example includes Mesopotamian artisans of the ninth century AD producing embedded NPs in glassy lms. By mixing Cu and Ag salts and oxides together with vinegar, ochre and clay on the surface of previously glazed pottery, glittering golden and copper colors were achieved upon annealing to ∼600°C in a reducing atmosphere to form Cu and Ag NPs (Borgia et al. 2002; Pradell et al. 2008).
