On the refractive index for a nonmagnetic two-component medium: resolution of a controversy

TL;DR

This paper resolves a controversy by demonstrating that a dielectric medium with passive and inverted components can have a negative real part of its refractive index, using both time and frequency domain methods.

Contribution

It introduces two complementary methods to determine the refractive index of complex dielectric media, clarifying the conditions for negative index behavior.

Findings

The medium exhibits a negative real part of the refractive index.

The methods confirm the active nature of the dielectric medium.

The controversy regarding the refractive index was conclusively resolved.

Abstract

The refractive index of a dielectric medium comprising both passive and inverted components in its permittivity was determined using two methods: (i) in the time domain, a finite-difference algorithm to compute the frequency-domain reflectance from reflection data for a pulsed plane wave that is normally incident on a dielectric half-space, and (ii) in the frequency domain, the deflection of an obliquely incident Gaussian beam on transmission through a dielectric slab. The dielectric medium was found to be an active medium with a negative real part for its refractive index. Thereby, a recent controversy in the scientific literature was resolved.