Diffraction-free optical beam propagation with near-zero phase variation in extremely anisotropic metamaterials

TL;DR

This paper demonstrates diffraction-free, deep-subwavelength optical beam propagation with near-zero phase variation in specially designed anisotropic metamaterials, achieved through engineering the permittivity tensor and analyzing nonlocal effects.

Contribution

The study introduces a novel design of anisotropic multilayer metamaterials with tailored permittivity for diffraction-free optical propagation at the nanoscale.

Findings

Achieved diffraction-free deep-subwavelength beam propagation.

Near-zero phase variation during propagation.

Effect of multilayer period and material loss analyzed.

Abstract

Extremely anisotropic metal-dielectric multilayer metamaterials are designed to have the effective permittivity tensor of a transverse component (parallel to the interfaces of the multilayer) with zero real part and a longitudinal component (normal to the interfaces of the multilayer) with ultra-large imaginary part at the same wavelength, including the optical nonlocality analysis based on the transfer-matrix method. The diffraction-free deep-subwavelength optical beam propagation with near-zero phase variation in the designed multilayer stack due to the near-flat iso-frequency contour is demonstrated and analyzed, including the effects of the multilayer period and the material loss.