On the sign of the refractive index for metamaterialsThe concept of the negative
refractive index with application to doubly negative metamaterials
The variation of the index of refraction in a vortex tube inhomogeneities. Expressions relating the
index of
refraction to the coordinate are obtained. The possibility
Superradiance in media with a near-zero refractive index on the modulus of a complex
refractive index approaching zero and on the ordering of optical centers is studied