Resolving the wave-vector and the refractive index from the coefficient of reflectance

Abstract

We resolve the existing controversy concerning the selection of the sign of the normal-to-the-interface component of the wave-vector $k_z$ of an electromagnetic wave in an active (gain) medium. Our method exploits the fact that no ambiguity exists in the case of a {\em film} of the active medium since its coefficient of reflectance is invariant under the inversion of the sign of $k_z$. Then we show that the limit of the infinite film thickness determines a unique and physically consistent choice of the wave-vector and the refractive index. Practically important implications of the theory are identified and discussed.

6 pages, 4 figures

References in corpus (4)

• A right-handed isotropic medium with a negative refractive index
• Resolving the wave-vector in negative refractive media: The sign of $\sqrt{Z}$
• On resolving the refractive index and the wave vector
• On the refractive index for a nonmagnetic two-component medium: resolution of a controversy

Cited by in corpus (5)

• On the electromagnetic properties of active media
• $\mathcal{P}\mathcal{T}$-Symmetry-Induced Wave Confinement and Guiding in Epsilon-Near-Zero Metamaterials
• When does the choice of the refractive index of a linear, homogeneous, isotropic, active, dielectric medium matter?
• Fourier theory of linear gain media
• Laplace-Fourier analysis and instabilities of a gainy slab