40
2 Zero-Index Metamaterials
(a) Hexagonal or triangular lattice of
rods [27]
(b) Honeycomb structure [112, 113]
(c) Square lattice of holes in dielectric [114]
(d) Dielectric veins [64]
(e) Star or flower shaped holes [115]
Fig. 2.13 Various designs of all-dielectric zero-index metamaterials
2.6.1 Propagation from Positive Index to Zero Index
Let us consider a beam of light traveling from air to a semi-infinite slab of zero refractive index medium. The zero-index media can be of three types, viz., epsilon-nearzero (ENZ), mu-near-zero (MNZ), and epsilon-mu-near-zero (EMNZ). We know
that the refractive index and the impedance of a medium are given as n =
√ and
z =
√
μ/, respectively. Considering normal incidence, for the sake of simplicity,
the reflection coefficient R is given by [66] (Figs. 2.14, 2.15 and 2.16)
2 Zero-Index Metamaterials
(a) Hexagonal or triangular lattice of
rods [27]
(b) Honeycomb structure [112, 113]
(c) Square lattice of holes in dielectric [114]
(d) Dielectric veins [64]
(e) Star or flower shaped holes [115]
Fig. 2.13 Various designs of all-dielectric zero-index metamaterials
2.6.1 Propagation from Positive Index to Zero Index
Let us consider a beam of light traveling from air to a semi-infinite slab of zero refractive index medium. The zero-index media can be of three types, viz., epsilon-nearzero (ENZ), mu-near-zero (MNZ), and epsilon-mu-near-zero (EMNZ). We know
that the refractive index and the impedance of a medium are given as n =
√ and
z =
√
μ/, respectively. Considering normal incidence, for the sake of simplicity,
the reflection coefficient R is given by [66] (Figs. 2.14, 2.15 and 2.16)