Advanced Optical Programming of Individual Meta‐Atoms Beyond the Effective Medium Approach. Issue 29 (27th May 2019)

• Record Type: Journal Article
• Authors: Michel, Ann‐Katrin U.; Heßler, Andreas; Meyer, Sebastian; Pries, Julian; Yu, Yuan; Kalix, Thomas; Lewin, Martin; Hanss, Julian; De Rose, Angela; Maß, Tobias W. W.; Wuttig, Matthias; Chigrin, Dmitry N.; Taubner, Thomas
• Is Part Of: Advanced materials. Volume 31:Issue 29(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-05-27
• Subjects: active metamaterials -- adaptive optics -- phase‐change materials -- programmable metasurfaces -- resonance tuning; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201901033
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Nanometer‐thick active metasurfaces (MSs) based on phase‐change materials (PCMs) enable compact photonic components, offering adjustable functionalities for the manipulation of light, such as polarization filtering, lensing, and beam steering. Commonly, they feature multiple operation states by switching the whole PCM fully between two states of drastically different optical properties. Intermediate states of the PCM are also exploited to obtain gradual resonance shifts, which are usually uniform over the whole MS and described by effective medium response. For programmable MSs, however, the ability to selectively address and switch the PCM in individual meta‐atoms is required. Here, simultaneous control of size, position, and crystallization depth of the switched phase‐change material (PCM) volume within each meta‐atom in a proof‐of‐principle MS consisting of a PCM‐covered Al–nanorod antenna array is demonstrated. By modifying optical properties locally, amplitude and light phase can be programmed at the meta‐atom scale. As this goes beyond previous effective medium concepts, it will enable small adaptive corrections to external aberrations and fabrication errors or multiple complex functionalities programmable on the same MS. Abstract : Advanced optical addressing of a metasurface covered with phase‐change material (PCM) is demonstrated by simultaneously controlling size, position, and crystallization depth of the optically switched PCM volume within each meta‐atom. By modifying optical properties locally, amplitude and light phase can be programmed at the meta‐atom scale, enabling small adaptive corrections or multiple complex functionalities on the same metasurface.