title: High efficiency near diffraction-limited mid-infrared flat lenses based on metasurface reflectarrays.
abstract: 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.
authors: Shuyan
authors: S
authors: Zhang
authors: Myoung-Hwan
authors: MH
authors: Kim
authors: Francesco
authors: F
authors: Aieta
authors: Alan
authors: A
authors: She
authors: Tobias
authors: T
authors: Mansuripur
authors: Ilan
authors: I
authors: Gabay
authors: Mohammadreza
authors: M
authors: Khorasaninejad
authors: David
authors: D
authors: Rousso
authors: Xiaojun
authors: X
authors: Wang
authors: Mariano
authors: M
authors: Troccoli
authors: Nanfang
authors: N
authors: Yu
authors: Federico
authors: F
authors: Capasso