Demonstration of Multiband Polarization Conversion and Near Perfect Absorption Using a Novel Metasurface

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Metasurfaces (MTSs) are planar artificial structures used to control the waves in a desired manner [1–2]. These engineered structures with ultrathin thickness have made it possible to manipulate the electromagnetic (EM) waves in an unprecedented manner, providing various useful functionalities, including anomalous reflection/refraction, polarization conversion, absorption, chemical and bio sensing, dynamic beam steering, vortex, Airy and Bessel beam generations and holographic image projection to name a few [2–4]. Besides the abovementioned, polarization conversion and absorption are the two important functionalities that can be realized from MTSs and is the recent hot topic of research, due to its applications in wireless communications, imaging, holography, stealth technology, sensing and many more [2–9]. Although almost near perfect absorption has been achieved in various frequency regimes using various MTSs [5, 6], however they still lake some features like polarization insensitivity, angular stability and multiband operation, etc. Therefore, there is a strong need to design MTS based absorbers which have the features of high angular stability, polarization independency, wide and multiple band operations and so forth. Similarly, Polarization conversion which have been realized in many frequency regimes using different MTS based structures [7–9]. However, there is still a huge space to make these polarization converters more efficient and with the feature of multi-band which might be more practical. For example, in a real time scenario we need a broad, multi-band and angularly stable polarization converter with high polarization conversion ratio (PCR). Moreover, it is highly demanding to design a MTS which can perform multiple tasks using the same shared aperture. Thus there is a strong desire to design a MTS which can perform polarization conversion in one case accompanied by some other useful functionality in the other case. In this article we present near perfect absorption and polarization conversion in different frequency bands, by designing a novel unit cell and then a MTS with their periodic arrangement in the two-dimensional spatial plane.