High Efficient Metadevices for Terahertz Beam Shaping

Metasurfaces supply a planar approach for flexible wavefront manipulation, thus facilitating the integration and minimization of optical elements, especially in terahertz (THz) range. High efficient THz metadevices are highly pursued at present. Here, we propose bilayer design to improve efficiency metadevice. Two silicon pillar arrays with distinguishing geometries integrated on single substrate. On one side, elliptical pillars, geometry optimized target frequency, spatially orientated realize desired Pancharatnam-Berry phase. other uniform circular pillars set suppress reflection. With this design, versatile such as lens, lens array, polarization fork grating, Bessel vortex generator, Airy beam generator demonstrated. Maximum up 95% frequency excellent flexibility verified. It provides practical strategy generation compact high-efficiency metadevices, which suit high-performance imaging communication apparatuses.