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Flat Lenses Formed by Photonic and Electromagnetic Crystals
Published in Filippo Capolino, Applications of Metamaterials, 2017
Pavel A. Belov, Constantin R. Simovski, Pekka Ikonen
As mentioned earlier, negative refraction and backward-wave effects are inherent to double-negative media, but both of these effects can be observed in other structures as well. For example, it is enough for the media to be a uniaxial dielectric to observe negative refraction [45,46]. In this case, negative refraction occurs when the refracted wave is a forward wave (both in general meaning and with respect to the interface). However, the all-angle negative refraction in a medium of perhaps discrete but isotropic morphology offers the unique tool to obtain the aberrationless high-quality optical images in flat layers.
Nanoscale Optics
Published in Vladimir I. Gavrilenko, Optics of Nanomaterials, 2019
Experimental results and numerical simulations obtained by (Parazzoli et al., 2003) are shown in Fig. 3.14. The deviation of a microwave beam freely propagating in air in NIM and Teflon wedge agreed with the theory very well thus experimentally verifying the concept of the negative index materials. Metamaterials with negative refraction may lead to the development of a superlens capable of imaging objects and fine structures that are much smaller than the wavelength of light (Pendry et al., 2006).
A Review of Chiral and Bianisotropic Composite Materials Providing Backward Waves and Negative Refractive Indices
Published in Filippo Capolino, Theory and Phenomena of Metamaterials, 2017
Cheng-Wei Qiu, Saïd Zouhdi, Ari Sihvola
In a broad sense, the word composite means made of two or more different parts. The different natures of constituents allow us to obtain a material in which the set of performance characteristics is greater than that of the components taken separately. The properties of composite materials result from the properties of the constituent materials, the geometrical distribution, and their interactions. Thus to describe a composite material it will be necessary to specify the nature of constituents, the geometry of the distribution, and macroscopic response. In the field of electrical engineering, the electromagnetics in composite materials are more important, since the electromagnetic behavior of rather complicated structures has to be understood in the design of new devices or in the exploration of new findings. In the last few years, there has been an increasing interest in the research community in the modeling and characterization of negative-index materials. Negative-index materials are a class of composite materials artificially constructed to exhibit exotic electromagnetic properties not readily found in naturally occurring materials. This type of composite materials refract light in a way that is contrary to the normal right-handed rules of electromagnetism. Researchers hope that the peculiar properties will lead to superior lenses and might provide a chance to observe some kind of negative analog of other prominent optical phenomena, such as reversal of the Doppler shift and Cerenkov radiation. When the dielectric constant (є) and magnetic permeability (μ) are both negative, waves can still propagate in such a medium. In this case, the refractive index in the Snell’s law is negative, an incident wave experiences a negative refraction at the interface, and we have a backward wave whose phase velocity is in the direction opposite to the direction of the energy flow.
Synthesis of new mesomorphic terphenyl derivatives: the influence of terphenylene and functional fragments on the mesomorphic properties and ligand exchange on quantum dots
Published in Liquid Crystals, 2021
V. S. Bezborodov, A. V. Finko, S. G. Mikhalyonok, Y. I. Derikov, G. А. Shandryuk, N. M. Kuz’menok, A. S. Arol, O. N. Karpov, R. V. Talroze
Optical metamaterials are artificially structured materials capable of producing new functionalities [1]. Metamaterials may possess specific physical properties such as for instance negative refraction index which cannot be met in conventional natural materials [2,3]. Hybrid nanostructured materials containing nanoparticles and liquid crystals represent a group of composite materials tending to self-assemble which is necessary for the creation of metamaterials. Liquid crystals are known to be anisotropic liquids that may affect the organisation of embedded nanoparticles (NP). As an example the publications of Reven [4,5], Hegmann [6] and Smalyukh [7,8] should be mentioned. Dirking and Shen published a big review [9] dedicated to the analysis of the perspectives of the usage of liquid crystals and mesomorphic phases in nanotechnologies. The role and influence of NP on the alignment of liquid crystals, conductivity and electro-optical behaviour of LC matrixes are discussed in [10–13]. At the same time the tendency appears directed at creation of materials based on the embedding of nanoparticles in LC polymers [14–17].
Designing and performance evaluation of metamaterial inspired antenna for 4G and 5G applications
Published in International Journal of Electronics, 2021
Harbinder Singh, Balwinder Singh Sohi, Amit Gupta
The recent growth of wireless communication systems has produced a great demand for compact size antennas that are capable of handling the harmful radiation’s effects on the human body. Metamaterial integrated antennas may be a good solution to meet such types of requirements. Double Negative (DNG) metamaterials are the unnatural material that may mimic the negative behaviour of permittivity as well as permeability. This negative behaviour leads to the negative refractive index which may exhibit many unnatural properties like backward wave propagation, negative refraction, inversion of Doppler effect and Snell’s law. Such kind of extraordinary properties may be useful in controlling the wave radiation behaviour of electromagnetic waves. The integration of metamaterial with patch antenna can lead to the remedial of many limitations. The metamaterial can be designed using CRLH (Composite Right Left Hand) theory by computing the circuit element’s values (Lai et al., 2004). The theory solely depends on the propagation behaviour of wave and classifies the transmission line into two types namely the Right Hand (RH) and Left Hand (LH) transmission line (Xu et al., 2011). Figure 8 represents the circuit equivalent model of loss-free CRLH lines.
Analysis of solitonic pulse propagation in metamaterials implemented in photonic crystals
Published in Journal of Modern Optics, 2020
Michelle Savescu, Syed B. Qadri, Kaisar Khan
Figure 1(a) shows a fabricated photonic crystal cavity coupler realized on an Indium Phosphide (InP) substrate. In earlier experiments [13], the device, Photonic Crystal cavity, shows slow light propagation which is wavelength selective. To investigate the soliton pulse propagation in these types of metastructures it is essential to study dispersion characteristics of the waveguides. For that we conducted a finite difference time domain (FDTD) simulation using crystalwave simulator. The results of the simulation of a CW launched at 1550 nm wavelenght are shown in Figure 1(b). The figure shows a scattered light wave propagation. The resonance cavity size and the material inside it determine the wavelength of the incident light that can be propagated. Different materials show different resonant wavelengths. This way the device can be used for sensing materials. Negative refraction can be observed at certain wavelengths; this is primarily due to the change of dispersion either by the choice of material or by altering the waveguide's geometry [9,10].