A single laser pulse can create complex, ordered nanostructure systems. “We have discovered a method for controlling the pattern into which the nanoparticles organize themselves”, says one of the physicists. The researchers started with a layer of disordered nanoparticles of gold or silver on a membrane of nanometer thickness. The patterning is a consequence of several transformations of the light, which finally results in partial melting and moving of the nanoparticles.