Chromatic devices such as flat panel displays could, in principle, be substantially improved by incorporating aluminum plasmonic nanostructures instead of conventional chromophores that are susceptible to photobleaching. In nanostructure form, aluminum is capable of producing colors that span the visible region of the spectrum while contributing exceptional robustness, low cost, and streamlined manufacturability compatible with semiconductor manufacturing technology. However, individual aluminum nanostructures alone lack the vivid chromaticity of currently available chromophores because of the strong damping of the aluminum plasmon resonance in the visible region of the spectrum. In recent work, we showed that pixels formed by periodic arrays of Al nanostructures yield far more vivid coloration than the individual nanostructures. This progress was achieved by exploiting far-field diffractive coupling, which significantly suppresses the scattering response on the long-wavelength side of plasmonic pixel resonances. In the present work, we show that by utilizing another collective coupling effect, Fano interference, it is possible to substantially narrow the short-wavelength side of the pixel spectral response. Together, these two complementary effects provide unprecedented control of plasmonic pixel spectral line shape, resulting in aluminum pixels with far more vivid, monochromatic coloration across the entire RGB color gamut than previously attainable. We further demonstrate that pixels designed in this manner can be used directly as switchable elements in liquid crystal displays and determine the minimum and optimal numbers of nanorods required in an array to achieve good color quality and intensity.

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Summary Adversaries can compute the secret information of a program, such as the key for encryption routines, from side channels in the light of timing‐based and access‐based CPU cache behaviours. As a result, it is crucial to understand whether a program is vulnerable to side‐channel cache leakage or not. Yet how we can find out such a vulnerability in a program remains a problem. In this paper, we revisit this problem and contemplate a test‐generation methodology, which, in both timing‐based and access‐based dimensions, systematically discovers the cache side‐channel leakage of an arbitrary software program. At the core of our test‐generation framework is an algorithm that explores the program's input space and adapts at runtime according to observed cache performance in the executed tests. We have implemented our test generator for timing‐based and access‐based attack tests and evaluated it with open‐source subject programs, including ones from OPENSSL and Linux GDK libraries. Our extensive evaluation effectively discloses the vulnerabilities of these real‐world software to both timing‐based and access‐based cache attacks. We also empirically show that our test generator achieves higher and comparable effectiveness, respectively, in simulations and real hardware platforms with regard to revealing cache side‐channel leakage than do state‐of‐the‐art fuzz testing tools.