Uniform Huygens Metasurfaces with Postfabrication Phase Pattern Recording Functionality

Description

With the rapid progress in the field of metasurfaces and their use in miniature integrated devices arise the quest for cheap mass production of efficient metasurfaces. We suggest a novel way to design and fabricate phase-gradient Huygens metasurfaces using laser-annealing of uniform particles made of As2S3 chalcogenide glass. We show that a phase gradient metasurface can be realized by tuning the refractive index of otherwise identical meta-atoms instead of tuning their geometry. We are using an array of identical As2S3 particles with the possibility to locally change their refractive index using a short-wavelength illumination (green laser) in order to tune the phase 1 pattern at the post-fabrication stage. Metasurfaces fabricated with this method can be used for operation in the red or IR spectral range. We fabricate uniform As2S3 Huygens metasurfaces using electron beam lithography and demonstrate their post-fabrication tuning with exposure of comparatively low intensity. Samples characterization with transmittance measurement and quantitative phase microscopy provide results in good correspondence with numerical predictions confirming post-fabrication spectral tuning. Using such tuning, we demonstrate the possibility to transfer the intensity pattern produced by modifying a writing beam with a spatial light modulator to a phase pattern recorded on a uniform As2S3 metasurface. Our method has potential advantages for the low-cost production of large-scale metasurfaces because uniform geometries are better adjusted for mass manufacturing.

Abstract

International audience

Additional details