Figure 1
APS/Carin Cain

Figure 1: Second-harmonic generation—the conversion of low-energy photons to higher-energy photons—is enhanced near a thin metallic film by surface plasmons. To excite plasmons, light is directed through a prism onto a metal nanofilm. Individual photons each excite surface plasmons, which can then combine to form a higher energy plasmon and photon. Here, plasmons are represented by curves indicating the intensity profile of their electric field, which decays exponentially away from the metal surface.