Trapping Monolayer of Colloidal Particles in a Laser Lattice with Aperiodic Structure

Although order is pleasing to the eye, it can quickly become boring. In Islamic architecture therefore, decoration often follows a strict yet aperiodic pattern. Similar structures also form in certain materials, called quasicrystals. Physicists from the University of Stuttgart and the Max Planck Institute of Metals Research have succeeded in trapping a monolayer of colloidal particles, tiny plastic spheres, in a laser lattice with an aperiodic structure. How the particles arrange themselves in this lattice strongly depends on the laser power. At high intensity, the particles form a quasicrystalline pattern; at low intensities, the particles instead position themselves into a periodic crystalline arrangement. The researchers were particularly surprised by what they observed at intermediate laser intensities: an... [read full story]