Hyper-gratings: nanophotonics in planar anisotropic metamaterials

TL;DR

This paper introduces a novel nanophotonic technique using planar anisotropic metamaterials and diffraction gratings to achieve subwavelength focal spots in the far-field, surpassing traditional limitations of superlenses and hyperlenses.

Contribution

It presents a new method combining gratings and anisotropic metamaterials for far-field subwavelength focusing, applicable across visible to mid-IR frequencies.

Findings

The technique can produce subwavelength focal spots in the far-field.

The approach is effective across multiple frequency ranges.

The method overcomes fundamental limitations of previous superlensing technologies.

Abstract

We present a technique capable of producing subwavelength focal spots in the far-field of the source in planar non-resonant structures. The approach combines the diffraction gratings that generate the high-wavevector-number modes and planar slabs of homogeneous anisotropic metamaterials that propagate these waves and combine them at the subwavelength focal spots. In a sense, the technique combines the benefits of Fresnel lens, near-field zone plates, hyperlens, and superlens, and at the same time resolves their fundamental limitations. Several realizations of the proposed technique for visible, near-IR, and mid-IR frequencies are proposed, and their performance is analyzed theoretically and numerically. Generalization of the developed approach for sub-diffractional on-chip photonics is suggested.