A Thickness Dependent Enhancement of Optical Resolution in the Vicinity of an Epsilon-near-zero Slab

TL;DR

This paper investigates how the thickness of an epsilon-near-zero (ENZ) slab affects optical resolution enhancement, finding an optimal thickness that significantly improves imaging of subwavelength structures.

Contribution

It introduces a detailed analysis of ENZ slab thickness dependence on resolution enhancement, identifying an optimal thickness for improved optical imaging.

Findings

Optimal ENZ thickness is 700 nm.

Achieved resolution of 11 μm at 8 μm wavelength.

Successful imaging of subwavelength slit arrays.

Abstract

Recent studies reports that an epsilon-near-zero (ENZ) thin slab between a specimen and a substrate contributes in enhancing the spatial resolution of the optical system. Here, we investigate the ENZ thickness dependence of the resolution enhancement. By employing the edge response function, the resolution of the optical system is directly measured when imaging a sharp edge of a metal film. We found that the optimum ENZ slab thickness was 700 nm and the achieved resolution was 11 {\mu}m at the wavelength of 8 {\mu}m. Owing to the enhanced resolution by ENZ slab, we successfully imaged the subwavelength slit arrays.