Chapter 3
Applications of Zero-Index
Metamaterials
3.1 Introduction
Exotic phenomena always have enchanting applications, so is the case with zero
refractive index. Zero-index metamaterials have several interesting applications
such as wavefront engineering, electromagnetic tunneling, electromagnetic cloaking, directivity enhancement by manipulation of the radiation pattern, etc. which
have been discussed in this chapter.
3.2 Electromagnetic Tunneling
In the previous chapter, it has been shown that there is no change in the phase of the
wave as it passes through a zero-index medium. The wave exits the ZIM with the
same phase as with which it enters, and the magnitude of the field remains the same
throughout the medium. This property can be exploited to achieve electromagnetic
tunneling through distorted channels. Distortions can be of several types, such as
shrinking, expansion, irregular shape, bending, etc. The tunneling phenomenon has
been discussed in detail, in the following.
3.2.1 Tunneling Using Epsilon-Near-Zero (ENZ) Materials
Suppose, in a photonic integrated circuit, light is required to travel from a broad
waveguide to a very narrow channel of subwavelength thickness. The impedance
mismatch between the waveguide and the narrow channel will be drastic. Therefore,
the reflection loss will be high, and coupling will be poor. However, if the narrow
channel is filled with an epsilon-near-zero material, the incident electromagnetic
wave gets squeezed into the channel and is almost entirely transmitted to the other
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
N. Shankhwar and R. K. Sinha, Zero Index Metamaterials,
https://doi.org/10.1007/978-981-16-0189-7_3
57
Applications of Zero-Index
Metamaterials
3.1 Introduction
Exotic phenomena always have enchanting applications, so is the case with zero
refractive index. Zero-index metamaterials have several interesting applications
such as wavefront engineering, electromagnetic tunneling, electromagnetic cloaking, directivity enhancement by manipulation of the radiation pattern, etc. which
have been discussed in this chapter.
3.2 Electromagnetic Tunneling
In the previous chapter, it has been shown that there is no change in the phase of the
wave as it passes through a zero-index medium. The wave exits the ZIM with the
same phase as with which it enters, and the magnitude of the field remains the same
throughout the medium. This property can be exploited to achieve electromagnetic
tunneling through distorted channels. Distortions can be of several types, such as
shrinking, expansion, irregular shape, bending, etc. The tunneling phenomenon has
been discussed in detail, in the following.
3.2.1 Tunneling Using Epsilon-Near-Zero (ENZ) Materials
Suppose, in a photonic integrated circuit, light is required to travel from a broad
waveguide to a very narrow channel of subwavelength thickness. The impedance
mismatch between the waveguide and the narrow channel will be drastic. Therefore,
the reflection loss will be high, and coupling will be poor. However, if the narrow
channel is filled with an epsilon-near-zero material, the incident electromagnetic
wave gets squeezed into the channel and is almost entirely transmitted to the other
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
N. Shankhwar and R. K. Sinha, Zero Index Metamaterials,
https://doi.org/10.1007/978-981-16-0189-7_3
57