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Photonic Fractal Metamaterials: A Metal–Semiconductor Platform with Enhanced Volatile‐Compound Sensing Performance
Author(s) -
Fusco Zelio,
Rahmani Mohsen,
TranPhu Thanh,
Ricci Chiara,
Kiy Alexander,
Kluth Patrick,
Della Gaspera Enrico,
Motta Nunzio,
Neshev Dragomir,
Tricoli Antonio
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202002471
Subject(s) - materials science , photonics , metamaterial , plasmon , fabrication , optoelectronics , semiconductor , fractal , photonic metamaterial , planar , nanotechnology , optics , physics , computer science , medicine , mathematical analysis , alternative medicine , mathematics , computer graphics (images) , pathology
Advance of photonics media is restrained by the lack of structuring techniques for the 3D fabrication of active materials with long‐range periodicity. A methodology is reported for the engineering of tunable resonant photonic media with thickness exceeding the plasmonic near‐field enhancement region by more than two orders of magnitude. The media architecture consists of a stochastically ordered distribution of plasmonic nanocrystals in a fractal scaffold of high‐index semiconductors. This plasmonic‐semiconductor fractal media supports the propagation of surface plasmons with drastically enhanced intensity over multiple length scales, overcoming the 2D limitations of established metasurface technologies. The fractal media are used for the fabrication of plasmonic optical gas sensors, achieving a limit of detection of 0.01 vol% at room temperature and sensitivity up to 1.9 nm vol% −1 , demonstrating almost a fivefold increase with respect to an optimized planar geometry. Beneficially to their implementation, the self‐assembly mechanism of this fractal architecture allows fabrication of micrometer‐thick media over surfaces of several square centimeters in a few seconds. The designable optical features and intrinsic scalability of these photonic fractal metamaterials provide ample opportunities for applications, bridging across transformation optics, sensing, and light harvesting.