Figure 22.3 — Trapping of plasmonic nanoparticles Figure 22.3 — Trapping of plasmonic nanoparticles. (a) Time evolution of the Rayleigh scattering spectrum from optically trapped silver nanoparticles, showing the evolution of the wavelength of the coupled plasmon resonance. p1, p2, p3 and p4 indicate the presence of one, two, three and four nanoparticles in the trap, respectively. (b) Measured scattered intensity spectrum and (c) calculated scattering cross-section for one, two and three nanoparticles.Reprinted with permission from Ohlinger et al., Nano Lett. 11, 1770–4. Copyright (2011) American Chemical Society.