Shedding new light on angle-selective Huygens’ metasurfaces (Vol. 49, No. 3)
Huygens’ metasurfaces form a class of ultra-thin optical devices which allow scientists to reshape the wavefront of an incident beam of light. Representatives of this class include highly efficient flat lenses, beam shapers, and holographic phase masks.
More specifically, such metasurfaces are composed of a carefully designed, two-dimensional arrangement of high-refractive-index dielectric nanoparticles, which show virtually no absorption losses and exhibit electric and magnetic dipole resonances known from Mie scattering. When these resonances are designed to overlap spectrally, the nanoparticles scatter almost all light in the forward-direction only, and thereby emulate the behavior of the forward-propagating elementary wavelets known from Huygens’ principle. The authors have investigated this effect in dependence on the incidence angle and polarization of incident plane waves for a metasurface composed of silicon nanocylinders. They showed that the resonance overlap can be designed to appear at an arbitrary incidence angle. Furthermore, since the metasurface blocks all light incident at angles other than the design angle, angle-selective functionalities may be implemented as well. These findings open interesting opportunities for the design of advanced wavefront-shaping devices and computer-generated holograms.
D. Arslan, K. E. Chong, A. E. Miroshnichenko, D.-Y. Choi, D. N. Neshev, T. Pertsch, Y. S. Kivshar and I. Staude, Angle-Selective All-Dielectric Huygens' Metasurfaces,
J. Phys. D: Appl. Phys. 50, 434002 (2017)