We address the question whether technological mishaps (inaccurate meta-atoms dimensions, shapes or positions) do really influence the response of a metasurface? Using both simulations and experiments on purposely miss-fabricated samples, we analyze the robustness of phase gradient metasurfaces. Surprisingly, we observe that a "perfect" structure, without any defects, is not the one that exhibits the best performance in terms of efficiency and angular response. Actually, we demonstrate that specific, well-controlled, defects can significantly enhance the performance of such a metasurface and explain this behavior using the resonance and near-field properties of the corresponding nanostructures.
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