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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| History of metamaterials | 1/5 | https://en.wikipedia.org/wiki/History_of_metamaterials | reference | science, encyclopedia | 2026-05-05T03:39:47.132262+00:00 | kb-cron |
The history of metamaterials begins with artificial dielectrics in microwave engineering as it developed just after World War II. Yet, there are seminal explorations of artificial materials for manipulating electromagnetic waves at the end of the 19th century. Hence, the history of metamaterials is essentially a history of developing certain types of manufactured materials, which interact at radio frequency, microwave, and later optical frequencies. As the science of materials has advanced, photonic materials have been developed which use the photon of light as the fundamental carrier of information. This has led to photonic crystals, and at the beginning of the new millennium, the proof of principle for functioning metamaterials with a negative index of refraction in the microwave- (at 10.5 Gigahertz) and optical range. This was followed by the first proof of principle for metamaterial cloaking (shielding an object from view), also in the microwave range, about six years later. However, a cloak that can conceal objects across the entire electromagnetic spectrum is still decades away. Many physics and engineering problems need to be solved. Nevertheless, negative refractive materials have led to the development of metamaterial antennas and metamaterial microwave lenses for miniature wireless system antennas which are more efficient than their conventional counterparts. Also, metamaterial antennas are now commercially available. Meanwhile, subwavelength focusing with the superlens is also a part of present-day metamaterials research.
== Early wave studies ==
Classical waves transfer energy without transporting matter through the medium (material). For example, waves in a pond do not carry the water molecules from place to place; rather the wave's energy travels through the water, leaving the water molecules in place. Additionally, charged particles, such as electrons and protons create electromagnetic fields when they move, and these fields transport the type of energy known as electromagnetic radiation, or light. A changing magnetic field will induce a changing electric field and vice versa—the two are linked. These changing fields form electromagnetic waves. Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate. This means that electromagnetic waves can travel not only through air and solid materials, but also through the vacuum of space. The "history of metamaterials" can have a variety starting points depending on the properties of interest. Related early wave studies started in 1904 and progressed through more than half of the first part of the twentieth century. This early research included the relationship of the phase velocity to group velocity and the relationship of the wave vector and Poynting vector. In 1904 the possibility of negative phase velocity accompanied by an anti-parallel group velocity were noted by Horace Lamb (book: Hydrodynamics) and Arthur Schuster (Book: Intro to Optics). However both thought practical achievement of these phenomena were not possible. In 1945 Leonid Mandelstam (also "Mandel'shtam") studied the anti-parallel phase and group advance in more detail. He is also noted for examining the electromagnetic characteristics of materials demonstrating negative refraction, as well as the first left-handed material concept. These studies included negative group velocity. He reported that such phenomena occurs in a crystal lattice. This may be considered significant because the metamaterial is a man made crystal lattice (structure). In 1905 H.C. Pocklington also studied certain effects related to negative group velocity. V.E. Pafomov (1959), and several years later, the research team V.M. Agranovich and V.L. Ginzburg (1966) reported the repercussions of negative permittivity, negative permeability, and negative group velocity in their study of crystals and excitons. In 1967, V.G. Veselago from Moscow Institute of Physics and Technology considered the theoretical model of medium that is now known as a metamaterial. However, physical experimentation did not occur until 33 years after the paper's publication due to lack of available materials and lack of sufficient computing power. It was not until the 1990s that materials and computing power became available to artificially produce the necessary structures. Veselago also predicted a number of electromagnetic phenomena that would be reversed including the refractive index. In addition, he is credited with coining the term "left handed material" for the present day metamaterial because of the anti-parallel behavior of the wave vector and other electromagnetic fields. Moreover, he noted that the material he was studying was a double negative material, as certain metamaterials are named today, because of the ability to simultaneously produce negative values for two important parameters, e.g. permittivity and permeability. In 1968, his paper was translated and published in English. He was nominated later for a Nobel prize. Later still, developments in nanofabrication and subwavelength imaging techniques are now taking this work into optical wavelengths.
== Early electromagnetic media ==
In the 19th century Maxwell's equations united all previous observations, experiments, and established propositions pertaining to electricity and magnetism into a consistent theory, which is also fundamental to optics. Maxwell's work demonstrated that electricity, magnetism and even light are all manifestations of the same phenomenon, namely the electromagnetic field. Likewise, the concept of using certain constructed materials as a method for manipulating electromagnetic waves dates back to the 19th century. Microwave theory had developed significantly during the latter part of the 19th century with the cylindrical parabolic reflector, dielectric lens, microwave absorbers, the cavity radiator, the radiating iris, and the pyramidal electromagnetic horn. The science involving microwaves also included round, square, and rectangular waveguides precluding Sir Rayleigh's published work on waveguide operation in 1896. Microwave optics, involving the focusing of microwaves, introduced quasi-optical components, and a treatment of microwave optics was published in 1897 (by Righi).