Antireflective “moth-eye” structures on tunable optical silicone membranes

Abstract

Flexible silicone membranes are key components for tunable optical lenses. The elastic operation of the membranes impedes the use of classical layer systems for an antireflective (AR) effect. To overcome this limitation, we equipped optical elastomer membranes with "moth-eye" structures directly in the flexible silicone substrate. The manufacturing of the AR structures in the flexible membrane includes a mastering process based on block copolymer micelle nanolithography followed by a replication method. We investigate the performance of the resulting AR structures under strain of up to 20% membrane expansion. A significant transmittance enhancement of up to 2.5% is achieved over the entire visible spectrum, which means that more than half of the surface reflection losses are compensated by the AR structures.

Fabrication of Broadband Antireflective Plasmonic Gold Nanocone Arrays on Flexible Polymer Films

“…Arrays of nanostructures such as nanocones, nanotips, nanopillars and nanowires have attracted great attention recently due to their notable characteristics such as broadband antireflection and light trapping properties, − strong hydrophobicity − and high surface area, with applications in photonic and photovoltaic devices, biological and chemical sensors and self-cleaning surfaces . To date, a variety of nanostructures created from metals, − semiconductors, ,,, oxides, ,, and polymers have been reported. For example, silicon nanostructured arrays are currently studied intensively, as their excellent antireflective properties can provide better efficiency in solar cell applications .…”

IR-laser assisted additive freeform optics manufacturing

“…Optical silicones, such as Polydimethylsiloxane (PDMS) and Dow Corning® MS-1002 Moldable Silicone, are typically used in LED lighting and other commercial applications 14 – 17 . Compared to UV curable materials, thermally curable optical silicones have a number of advantages, such as strong UV stability, non-yellowing, and high transmission, making it particularly suitable for optical imaging applications 18 .…”

Antireflection of optical anisotropic dielectric metasurfaces

“…A traditional antireflective thin-film consists of single or multiple homogeneous layers and has refractive indices and thicknesses suitable for reducing the Fresnel reflection at the interface. Sub-wavelength structures, such as gratings 22 , pillars 23 , 24 , pyramids 25 , 26 , moth-eyes 27 – 29 , and nanopores 30 , may also be used for antireflection. These structures generate a gradient effective refractive index to reduce the refractive index contrast between air and the medium through which light is entering.…”