Causality-Based Criteria for a Negative Refractive Index Must Be Used With Care

Causality-based criteria for a negative refractive index must be used with care.

Using the principle of causality as expressed in the Kramers-Kronig relations, we derive a generalized criterion for a negative refractive index that admits imperfect transparency at an observation frequency omega. It also allows us to relate the global properties of the loss (i.e., its frequency response) to its local behavior at omega. However, causality-based criteria rely on the group veloc...

Negative Refractive Index Materials

Negative Refractive Index Materials Victor Veselago,1 Leonid Braginsky,2 Valery Shklover,3 and Christian Hafner4 ∗ 1Laboratory of Magnetic Materials, A. M. Prokhorov Institute of General Physics, 38 Vavilov Street, 119991 Moscow, Russia 2Institute of Semiconductors’ Physics, 13 Lavrent’eva Pr., 630090 Novosibirsk, Russia 3Laboratory of Crystallography, ETH Zürich, CH-8093 Zürich, Switzerland 4L...

Negative refractive index metamaterials

a negative index of refraction over a band of microwave frequencies1. This demonstration of a previously unexploited electromagnetic (EM) property proved the importance of engineered materials and has resulted in an extraordinary amount of continued development by scientists working in optics, electromagnetism, physics, engineering, and materials science. Experimental results revealing new phen...

Resonant Negative Refractive Index Metamaterials

Metrics for negative-refractive-index materials.

The importance of loss in the field solution for left-handed media, and in particular, the impact on what would otherwise be a purely evanescent field, is addressed. Using an equivalent electric current source, field solutions are constructed in semi-infinite and finite thickness left-handed media. In the slab case, field growth and power dissipation metrics with uniform amplitude and uniform p...