Experimental Demonstration of In-Plane Negative-Angle Refraction with an Array of Silicon Nanoposts

Abstract

Controlling an optical beam is fundamental in optics. Recently, unique manipulation of optical wavefronts has been successfully demonstrated by metasurfaces. However, these artificially engineered nanostructures have thus far been limited to operate on light beams propagating out-of-plane. The in-plane operation is critical for on-chip photonic applications. Here, we demonstrate an anomalous negative-angle refraction of a light beam propagating along the plane, by designing a thin dielectric array of silicon nanoposts. The circularly polarized dipoles induced by the high-permittivity nanoposts at the scattering resonance significantly shape the wavefront of the light beam and bend it anomalously. The unique capability of a thin line of the nanoposts for manipulating in-plane wavefronts makes the device extremely compact. The low loss all-dielectric structure is compatible with complementary metal-oxide semiconductor technologies, offering an effective solution for in-plane beam steering and routing for on-chip photonics.

Beam Steering with Dielectric Metalattices

“…Refs. 29,38 ), we further demonstrate that such large-angle high-efficiency beam steering is also achievable for s-polarized waves. The related spectra with d = 5.1R and λ = 6.24R is shown in Fig.…”

Scattering Invisibility With Free‐Space Field Enhancement of All‐Dielectric Nanoparticles

“…where α is the scattering angle and k α = (k x , k y ) = (k cos α, k sin α). It is worth mentioning that in coupled nanowire systems usually a s,p jm = a s,p j−m [31], and for specific calculations, we would truncate the cylindrical harmonic number after the results become convergent. Then according to the optical theorem [26], the extinction efficiency for the whole system of the coupled nanowires is:…”

Generalized Kerker effects in nanophotonics and meta-optics [Invited]

“…Consequently, as generalized Kerker effects can be employed to shape the angular scattering of each unit cell, the principles of multipolar interference can certainly provide extra opportunities for diffraction management in meta-optics. Higher-order diffraction management in metalattices has been demonstrated in the dipolar regime (where only interference between ED and MD modes is employed to shape the unit-cell scattering [129][130][131][132]), and also in more general multipolar regimes where higher-order multipoles are taken into account [118,133,134]. Two such examples with higher-order interfering multipoles are shown in Fig.…”