Figure 12.4 — Experimental realisation of colloidal quasicrystals Figure 12.4 — Experimental realisation of colloidal quasicrystals. (a) Five linearly polarised (polarisation as indicated by arrows) parallel laser beams forming a regular pentagon are focused into a thin sample cell. (b) Experimentally determined intensity distribution of the interference pattern, which acts as a substrate potential for the colloids. The pattern displays a decagonal symmetry and the predominating motifs are pentagons (indicated in white) with sides of different lengths related by the golden ratio τ = S/L. Here S = 5.64 μm and L = 9.13 μm. The shades of grey of the intensity field reflect the variation in potential well depth. (c) Configuration of colloidal particles at a density of 0.0264 particles/μm exposed to a decagonal substrate interference pattern.Reprinted by permission from Macmillan Publishers Ltd: Mikhael et al., Nature 454, 501–4, copyright 2008.