Near-Field Optical control of Doughnut-Shaped Nanostructures
  The application of a local near-field optical excitation can be used to control step-by-step the reshape of individual doughnut-shaped azopolymer nano-objects by varying the time of illumination demonstrating its promising performance as a functional nano-object. The possibility to provide both photoinduced reshaping opens a way to the fundamental study of size-dependent scaling laws of optical properties, photoinduced reshaping efficiency and nanoreactor or nanoresonator behavior at nanometer scale. As an example the nano-object is used to self-assembly polystyrene nanospheres in a supraball. 
A. M. Dubrovkin, R. Barille, E. Ortyl, S. Zielinska
physics.optics