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Franck Carcenac

Publications and source records attributed to Franck Carcenac.

2 recordsLinked to original sources

Extrinsic Limitations of Stealthy Hyperuniform devices

Hyperuniformity promises an unusual form of wave control: the suppression of elastic scattering over extended angular ranges without periodic order. Here, we present a comprehensive experimental and theoretical study of 2D stealthy hyperuniform metasurfaces operating at optical frequencies. In agreement with theoretical expectations, we observe a pronounced reduction of elastic scattering around the specular direction in metasurfaces fabricated by electron-beam lithography. However, the measured suppression is substantially weaker than that predicted by structure-factor calculations based on ideal stealthy hyperuniform point-pattern generators. We identify and quantitatively analyze the physical origins of this discrepancy and establish realistic performance bounds. By isolating the dominant limiting mechanisms, our results provide practical design guidelines for the implementation of stealthy hyperuniformity in functional devices.

physics.optics

Emergent scattering regimes in disordered metasurfaces near critical packing

Disordered metasurfaces provide a versatile platform for harnessing near- and far-field scattered light. Most research has focused on either particulate topologies composed of individual, well-identified metaatoms or, to a lesser extent, semi-continuous aggregate topologies without well identified inclusions. Here, we uncover an intermediate critical packing regime characterized by metasurface morphologies in which a significant fraction of metaatoms begin to connect. We experimentally demonstrate that, at this threshold, the properties of the scattered light abruptly change and, via a statistical quasinormal mode analysis, interpret this change as a marked transition in the statistics of the photon density of states. Unlike percolation in semicontinuous metal films, this transition affects not only the specular but also the diffuse components of the scattered light in a profound way. Our results introduce critical packing topologies as a novel design strategy for manipulating the spectral and angular characteristics of light using ultrathin optical coatings. Emergent functionalities include colour shifts in diffuse light driven by multiple scattering and surface whitening, with potential applications in display technologies, for example, to reduce glare in electronic screens.

physics.optics