Sign of refractive index and group velocity in left-handed media

2002/09/19 by A. L. Pokrovsky, A. L. Efros, Alexander L. Efros · 2 citations
Engineering · Materials Science · Physics and Astronomy · #Metamaterials and Metasurfaces Applications #Photonic Crystals and Applications #Plasmonic and Surface Plasmon Research #cond-mat

paper · pdf · doi:10.1016/s0038-1098(02)00553-7

10 pages 2 figures

arxiv created 2002/09/19 · openalex publication_date 2002/11/01 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We argue that the widely spread opinion that the left-handed media (LHM) are characterized by a negative refractive index n_- is misleading. Since n does not enter into Maxwell's equations and boundary conditions, any medium may be described by both positive n and negative n_-=-n. Two thermodynamic inequalities are presented, that make a difference between the LHM and the regular media (RM). The first one reads that the group velocity is positive in the RM and negative in the LHM. The second one is that the product \rm Re(n) \rm Im(n) is positive in the RM and negative in the LHM. Both inequalities are invariant with respect to the change n → n_-. However, to use n_- one should change some traditional electrodynamics definitions.

Citations

• THE ELECTRODYNAMICS OF SUBSTANCES WITH SIMULTANEOUSLY NEGATIVE VALUES OF ε AND μ
• Determination of Effective Permittivity and Permeability of Metamaterials from Reflection and Transmission Coefficients

Cited by

• Negative Refraction in Perspective
• Causality-Based Criteria for a Negative Refractive Index Must Be Used With Care