Fig. 1
From: Recent advancements of metalenses for functional imaging
Materials for metasurfaces and metalenses. a Schematic of plasmonic metalens and (inset) corresponding scanning electron microscopy (SEM) image (scale bar = 1 μm). Reproduced with permission [39] (Copyright 2012, Springer Nature). b Structure of MIM metasurface. MgF2 and gold films are located below the gold nanorod, leading to Fabry-Pérot-like behavior. Reproduced with permission [93] (Copyright 2015, Springer Nature). c SEM image of fabricated dielectric gradient metalens. d Measured intensity profile of metalens in xz-plane. c and d are reproduced with permission [94] (Copyright 2014, American Association for the Advancement of Science). e Comparison of visible transparency of (left) conventional and (right) low-loss a-Si:H. f Captured images of beam steering by low-loss a-Si:H metasurfaces. Deflected light with wavelengths of (top) 450 nm, (middle) 532 nm, and (bottom) 635 nm are shown. (e) and (f) are reproduced with permission [95] (Copyright 2021, Wiley-VCH).