Magnetically programmed diffractive robotics.

Microscopic robots with features comparable with the wavelength of light offer new ways of probing the microscopic world and controlling light at the microscale. We introduce a new class of magnetically controlled microscopic robots (microbots) that operate at the visible-light diffraction limit, which we term diffractive robots. We combined nanometer-thick mechanical membranes, programmable nanomagnets, and diffractive optical elements to create untethered microbots small enough to diffract visible light and flexible enough to undergo complex reconfigurations in millitesla-scale magnetic fields.

Effects of symmetry-breaking on electromagnetic backscattering.

Systems with a discrete rotational symmetry [Formula: see text] where [Formula: see text] that also have electromagnetic duality symmetry exhibit zero backscattering. The impact of breaking one of the two symmetries on the emerging backscattering has not yet been systematically studied. Here, we investigate the effect that perturbatively breaking each of the two symmetries has on the backscattering off individual objects and 2D arrays.