Pyramid-shaped ultra-stable gold-helix metamaterial as an efficient mid-infrared circular polarizer

Abstract Gold-helix metamaterials play a crucial role in tailoring chiral light-matter interactions. However, conventional gold helices with weak mechanical stability are easy to break or collapse, resulting in device failure. Here, we propose a novel ultra-stable pyramid-shaped gold-helix metamaterial in which we utilize photoresist walls to support tapered gold helices to address this challenge. Numerical results show that the proposed ultra-stable metamaterial can work as an efficient mid-infrared circular polarizer in almost two octaves (from 5.82 to 16.76 μ m) with a maximum extinction ratio greater than 25 dB. The device has many potential applications in circular polarization-dependent optical systems without worrying about vibrations.