Planar cascaded triangular hyperlens structures.

Abstract

Planar-ports hyperlens structures made of two or four cascaded triangular cuts of planar periodic structures are presented. The hyperlenses are capable of converting electromagnetic evanescent fields to propagating waves, featuring subwavelength resolution and image magnification. One of the two proposed structures features parallel input and output ports. The proposed structures improve the phase and amplitude unbalances, magnification, and resolution of previous planar hyperlenses. Compared to several previous cylindrical hyperlens structures, the proposed structures show competitive or better features. One of the best designs of the proposed structures offers a magnification of 3.86, a resolution of 45 nm, $\lambda /{8}$λ/8 at the free space wavelength of 365 nm, optical modulation, a measure of image contrast of 0.286, and amplitude unbalance, a measure of image quality of 0.08, the smallest among all previous structures. Detailed comparative data of performance are provided. Although the magnification of the proposed planar structures is somewhat smaller than some of the previous cylindrical ones, the performance of the proposed hyperlenses is better or competitive with respect to resolution and image quality.