High-Efficiency All-Dielectric Huygens Metasurfaces from the Ultraviolet to the Infrared

Abstract

Conventional optics depend on the gradual accumulation of spatially dependent phase shifts imparted on light propagating through a medium to modify the wavefront of an incident beam. A similar effect may be obtained by the imposition of abrupt, discrete phase changes on a propagating wavefront over a subwavelength scale using photonic metasurfaces. Highly efficient metasurfaces have applications ranging from conventional optics to high-efficiency solar energy conversion, optical communications, and more. We present here the design, computational modeling, and experimental demonstration of all-dielectric transmissive Huygens metasurfaces exhibiting anomalous refraction, defined as the controlled deflection of light at an interface as a function of subwavelength nanostructures. These metasurfaces are composed of dielectric, cylindrical elements, characterized by balanced electric and magnetic dipole resonances. For infrared wavelengths, optical efficiency of 91.3% is demonstrated computationally, and experimental efficiency of 63.6% is measured. Metasurfaces are designed and modeled in each of three experimentally realizable material systems, corresponding to incident wavelengths in the ultraviolet, visible, and infrared, all demonstrating high optical efficiency of at least 78%. A ground-up approach is presented that enables this design of highly efficient all-dielectric Huygens metasurfaces with nonzero phase gradients, in spite of difficulties due to strong interantenna coupling effects. Additionally, we computationally demonstrate a stacked metasurface device, capable of independent manipulation of four adjacent spectral bands, with midband optical efficiency as high as 55%. Taking advantage of the high sensitivity of this resonant dielectric Huygens metasurface approach, we discuss routes to the development of optical sensors and dynamically tunable metasurfaces.