Can Maxwell's Fish Eye Lens Really Give Perfect Imaging? Part II. The case with drains

TL;DR

This study uses numerical simulations to investigate Maxwell's fish eye lens with passive drains, revealing that the lens does not produce perfect imaging and that observed subwavelength spots are due to local field enhancement, not perfect focusing.

Contribution

The paper demonstrates through simulations that passive drains do not enable perfect imaging in Maxwell's fish eye lens, challenging previous assumptions about its resolution capabilities.

Findings

Passive drains do not produce perfect images in Maxwell's fish eye lens.

Subwavelength spots are caused by local field enhancement, not the lens's focusing ability.

The resolution remains finite even with passive drains present.

Abstract

We use both FEM (finite element method) and FDTD (finite difference time domain method) to simulate the field distribution in Maxwell's fish eye lens with one or more passive drains around the image point. We use the same Maxwell's fish eye lens structure as the one used in recent microwave experiment [arXiv:1007.2530]: Maxwell's fish eye lens bounded by PEC (perfect electric conductor) is inserted between two parallel PEC plates (as a waveguide structure). Our simulation results indicate that if one uses an active coaxial cable as the object and set an array of passive drains around the image region, what one obtains is not an image of the object but only multiple spots resembling the array of passive drains. The resolution of Maxwell's fish eye is finite even with such passive drains at the image locations. We also found that the subwavelength spot around the passive drain is due to the local field enhancement of the metal tip of the drain rather than the fish eye medium or the ability of the drain in extracting waves.