Spiral hyperlens with enhancements of image resolution and magnification |
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Authors: | Yi-An Chen I-Ling Chang |
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Affiliation: | Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan |
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Abstract: | AbstractA subwavelength spiral hyperlens that is able to image beyond the diffraction limit is studied. The spiral hyperlens is made from an anisotropic metamaterial with a hyperbolic dispersion relation in which the evanescent wave is converted into a propagating wave. Therefore, the propagating wave can be processed by conventional optical systems outside of the spiral hyperlens. The possibility of using a cylindrical hyperlens for overcoming the diffraction limit has been proven analytically and experimentally. In this study, we designed two types of spiral hyperlenses composed of a spiral periodic stack of silver and alumina multilayers. A spiral hyperlens utilizes the spiral geometry to magnify the objects. In comparison with a cylindrical hyperlens, a spiral hyperlens has improved performance in terms of higher image resolution and better image magnifications. Numerical simulations illustrate that the far-field imaging resolution of cylindrical spiral hyperlens is no greater than 110 nm at 365 nm working wavelength. |
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Keywords: | Hyperlens spiral hyperlens diffraction limit far-field imaging metamaterial nano-optics |
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