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Sunday, July 31, 2016
Abstract-High efficiency near diffraction-limited mid-infrared flat lenses based on metasurface reflectarrays
High efficiency near diffraction-limited mid-infrared flat lenses based on metasurface reflectarrays
Shuyan Zhang, Myoung-Hwan Kim, Francesco Aieta, Alan She, Tobias Mansuripur, Ilan Gabay, Mohammadreza Khorasaninejad, David Rousso, Xiaojun Wang, Mariano Troccoli, Nanfang Yu, and Federico Capasso
We report the first demonstration of a mid-IR reflection-based flat lens with high efficiency and near diffraction-limited focusing. Focusing efficiency as high as 80%, in good agreement with simulations (83%), has been achieved at 45° incidence angle at λ = 4.6 μm. The off-axis geometry considerably simplifies the optical arrangement compared to the common geometry of normal incidence in reflection mode which requires beam splitters. Simulations show that the effects of incidence angle are small compared to parabolic mirrors with the same NA. The use of single-step photolithography allows large scale fabrication. Such a device is important in the development of compact telescopes, microscopes, and spectroscopic designs.