Paraxial full-field cloaking

TL;DR

This paper extends paraxial ray optics cloaking to full-field light, demonstrating that an isotropic plate with tailored refractive index can achieve broadband, omnidirectional cloaking, revealing fundamental limits and conditions for anisotropy.

Contribution

It advances cloaking theory from paraxial approximation to full-field, showing how to design isotropic materials for broadband, omnidirectional cloaking.

Findings

Isotropic plates can achieve broadband cloaking with proper design.

Omnidirectionality is the key relaxed parameter for ideal cloaking.

Fundamental limits on broadband versus omnidirectional cloaking are supported.

Abstract

We complete the `paraxial' (small-angle) ray optics cloaking formalism presented previously [Choi and Howell, Opt. Express 22, 29465 (2014)], by extending it to the full-field of light. Omnidirectionality is then the only relaxed parameter of what may be considered an ideal, broadband, field cloak. We show that an isotropic plate of uniform thickness, with appropriately designed refractive index and dispersion, can match the phase over the whole visible spectrum. Our results support the fundamental limits on cloaking for broadband vs. omnidirectionality, and provide insights into when anisotropy may be required.