Figure 16.5 — Selective optical trapping with a photonic crystal cavity Figure 16.5 — Selective optical trapping with a photonic crystal cavity. (a) SEM image of a hollow photonic crystal structure with two distinct nanocavities resonant at two different wavelengths, λ1 = 1568 nm and λ2 = 1578 nm, as schematically illustrated in (b). (c) Demonstration of selective particle trapping when cavity 1 is excited and of particle release from the trap when excitation is switched to cavity 2. (d) Trapping when cavity 2 is excited and release when switching to cavity 1.Reproduced by permission from Descharmes et al., Lab Chip 13, 3268–74. Copyright (2013) The Royal Society of Chemistry.