Influences of source displacement on the features of subwavelength imaging of a photonic crystal slab

TL;DR

This study examines how source displacement affects subwavelength imaging in photonic crystal slabs, revealing sensitivities and ways to improve stability through material absorption and slab width adjustments.

Contribution

It provides new insights into the impact of source displacement on photonic crystal superlens imaging and suggests methods to enhance imaging stability.

Findings

Imaging properties are highly sensitive to source displacement.

Material absorption and slab width can improve imaging uniformity.

Displacement affects resolution and stability of the images.

Abstract

In this paper we study the characteristics of subwavelength imaging of a photonic crystal (PhC) superlens under the influence of source displacement. For square- and triangular-lattice photonic crystal lenses, we investigate the influence of changing the lateral position of a single point source on the imaging uniformity and stability. We also study the effect of changing the geometrical center of a pair of sources on the resolution of the double-image. Both properties are found to be sensitive to the displacement, which implies that a PhC slab cannot be treated seriously as a flat lens. We also show that by introducing material absorption into the dielectric cylinders of the PhC slab and widening the lateral width of the slab, the imaging uniformity and stability can be substantially improved. This study helps us to clarify the underlying mechanisms of some recently found phenomena concerning imaging instability.