Sébastien R. L. Guenneau

Invisibility cloaks for flexural waves have mostly been examined in a continuous-wave regime, while invisibility is likely to deteriorate for short pulses. Here, we propose the practical realization of a unidirectional invisibility cloak for flexural waves based on an area-preserving coordinate transformation. Time-resolved experiments reveal how the invisibility cloak deviates a pulsed plane wave from its initial trajectory and how the initial wavefront perfectly recombines behind the cloak, leaving the diamond-shaped hole invisible, notwithstanding the appearance of a forerunner. Three-dimensional full-elasticity simulations support our experimental observations.

We study electromagnetic forces and torques experienced on both perfect and discretized transformation-based concentrators, under time-harmonic illumination. The effect of the concentration is investigated in both cases and compared to the case of a perfect cloak. The effect of a Lorentz dispersion model on the optical force and torque is also investigated, and the force experienced by a dielectric particle located at the center of the concentrator is studied.