Figure 5.

Experimental (a) and calculated (b) transmittance spectra at normal incidence of 500 nm lattice parameter plasmonic meta-molecule arrays (30 nm Au nanoparticle clusters). The glass substrate refractive index is n = 1.49 at λ = 750 nm, while the superstrates were air (n = 1, light gray line), ethylene glycol (n = 1.419 at λ = 750 nm, green line), immersion oil (n = 1.506 at λ = 750 nm, red line), and epoxy SU-8 (n = 1.58 at λ = 750 nm, blue line). The calculated structure is a plasmonic crystal composed of 19–37 Au clusters with the Au diameter is 28 and 2 nm interparticle distance.