Semiconductor nanopillars for programmable directional lasing emissions

Mie resonances facilitate an efficient manipulation of light on the subwavelength scale in high-refractive-index metasurfaces. These ultra-thin high-refractive-index nanostructures have been utilized in wave-front engineering devices for amplitude and phase modulation on the subwavelength scale in dielectric metasurfaces with high transmission efficiencies. We seek to establish a guideline for the desired phase modulation of each element in the metasurfaces integrated with light-emitting devices. Numerical simulations of gallium arsenide (GaAs) nanopillar metasurfaces are carried out over the visible and near-infrared spectral ranges. We analyze the scattering properties of the nanopillars of various sizes along with reflection, transmission, absorption, and phase-change spectra of the nanopillar arrays. We study phase-change properties of nanopillars of varied radii along the spectrum and elaborate on the scattering features of the metasurfaces to create a library of phase-change characteristics. The results indicate that the nanostructures respond with strong resonances and the corresponding phase-change features in the visible and near-infrared frequencies. By the variation of the nanopillar dimensions, one can control the light phase change and shift the features along the spectrum.