John Brian Pendry | |
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Born | [1] | 4 July 1943
Nationality | British |
Alma mater | Downing College, Cambridge [1] |
Known for | |
Awards |
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Scientific career | |
Fields | Physicist |
Institutions | |
Thesis | The application of pseudopotentials to low energy electron diffraction (1970) |
Doctoral advisor | Volker Heine |
Website | www3 www |
Sir John Brian Pendry, FRS HonFInstP (born 4 July 1943 [2] [3] ) is an English theoretical physicist known for his research into refractive indices and creation of the first practical "Invisibility Cloak". He is a professor of theoretical solid state physics at Imperial College London where he was head of the department of physics (1998–2001) and principal of the faculty of physical sciences (2001–2002). He is an honorary fellow of Downing College, Cambridge, (where he was an undergraduate) and an IEEE fellow. [4] He received the Kavli Prize in Nanoscience "for transformative contributions to the field of nano-optics that have broken long-held beliefs about the limitations of the resolution limits of optical microscopy and imaging.", together with Stefan Hell, and Thomas Ebbesen, in 2014.
Pendry was educated at Downing College, Cambridge, graduating with a Master of Arts degree in Natural Sciences and a PhD in 1969. [5]
John Pendry was born in Manchester, where his father was an oil representative, and took a degree in Natural Sciences at the Downing College, Cambridge after which he was appointed as a research fellow, between 1969 and 1975. He spent time at Bell Labs in 1972–3 and was head of the theory group at the SERC Daresbury Laboratory from 1975 to 1981, when he was appointed to the chair in theoretical physics at Imperial College, London, where he stayed for the rest of his career. Preferring administration to teaching, he was Dean of the Royal College of Science from 1993 to 1996, head of the Physics Department from 1998 to 2001 and Principal of the Faculty of Physical Sciences 2001–2. He has authored over 300 research papers and encouraged many experimental initiatives. [2] [6]
He was elected a Fellow of the Royal Society in 1984 and in 2004 he was knighted in the Birthday Honours. [7] [8] In 2008, an issue of Journal of Physics: Condensed Matter was dedicated to him in honour of his 65th birthday.
He is married to Pat, a mathematician he met at Cambridge who became a tax inspector. They have no children. His hobbies include playing the piano. [6]
Pendry has authored or co-authored a wide range of articles [9] [10] [11] [12] [13] [14] and several books. [15] [16]
Pendry's research career started with his PhD, which was concerned with Low-energy electron diffraction (LEED), [5] a technique for examining the surface of materials which had been discovered in the twenties but which waited for Pendry's method of computing the results to become practical. His supervisor, Volker Heine observed that Pendry "is one of the few research students that I have had who did things independently that I could never have done myself". At Bell Labs, Pendry worked with Patrick Lee in photoelectron spectroscopy to develop the first quantitative theory of EXAFS, for which he was awarded the Dirac Prize of the Institute of Physics in 1996. [2]
Pendry noticed that the problem of photoemission was similar to his work on LEED and this was important as the synchrotron at Daresbury was just coming online. As head of the theory group there he published his theory of angle-resolved photoemission which remains the standard model in the field. These methods enabled the band structure of electrons in solids and at surfaces to be determined to unprecedented accuracy and in 1980 he proposed the technique of inverse photoemission which is now widely used for probing unoccupied electron states.
Whilst maintaining his position as the UK's leading theoretical surface physicist, at Imperial he began to study the behaviour of electrons in disordered media and derived a complete solution of the general scattering problem in one dimension and advanced techniques for studying higher dimensions, which are relevant to conductivity of bio-molecules. In 1994 he published his first papers on photonic band structures enabling the interaction of light with metallic systems to be discovered. This led to his invention of the idea of metamaterials. Currently, the idea of metamaterials has evolved from its initial focus on electromagnetic or optical wave systems [12] [13] - the first stage, to other wave systems [17] - the second stage, and has further expanded to diffusion systems [18] [19] [20] - the third stage. The control equations for these three stages are completely different, [21] [22] namely Maxwell equations (a type of wave equation for transverse waves), other wave equations (used to describe both longitudinal and transverse waves), and diffusion equations (used to describe diffusion processes). Therefore, from the perspective of control equations, researchers today can divide the field of metamaterials into three main branches: Electromagnetic/Optical wave metamaterials, other wave metamaterials, and diffusion metamaterials. Diffusion metamaterials are crafted to master various diffusion dynamics, where diffusion length serves as the pivotal measure. This parameter fluctuates over time, yet it does not respond to alterations in frequency. Conversely, wave metamaterials, tailored to modify diverse wave travel patterns, hinge on the wavelength of the incoming waves as their vital measure. Unlike diffusion length, wavelength stays steady over time but varies with frequency changes. At their core, the primary measures of diffusion and wave metamaterials diverge significantly, highlighting a unique complementary connection between the two; more details can be found in Section I.B "Evolution of metamaterial physics" of Ref. [21]
An article in Physical Review Letters in 2000 which extended work done by Russian scientist Victor Veselago and suggested a simple method of creating a lens whose focus was theoretically perfect, has become his most cited paper. [9] Initially, it had many critics who could not believe that such a short article could present such a radical idea. However his ideas were confirmed experimentally and the notion of the superlens has revolutionised nanoscale optics. [2]
In 2006 he came up with the idea of bending light in such a way that it could form a container around an object which effectively makes the object invisible and produced a paper with David R. Smith of Duke University, who demonstrated the idea at the frequency of microwaves. This idea, commonly known as the Invisibility cloak, has stimulated much recent work in the field of metamaterials. [23] In 2009 he and Stefan Maier received a large grant from the Leverhulme Trust to develop the ideas of perfect lens and invisibility cloak in the optical range of light. [24]
In 2024, Pendry was awarded the Kyoto Prize in Advanced Technology in the category of "Material Sciences and engineering".
Pendry, Sheldon Schultz and David R. Smith were selected as Clarivate Citation laureates in Physics "for their prediction and discovery of negative refraction." [25]
In 2019, Pendry won the SPIE Mozi Award "in recognition of his eminent contributions to the development of perfect lens" [26]
In 2016, Sir John Pendry was awarded the Dan David Prize.
In 2014, he was a co-recipient of the Kavli Prize in Nanoscience, awarded by the Norwegian Academy of Science and Letters, with Stefan Hell of the Max Planck Institute for Biophysical Chemistry, and Thomas Ebbesen of the University of Strasbourg. [27]
In 2013, he won the Institute of Physics Isaac Newton Medal. [28]
In 1994, he was a recipient of the BVC Medal and Prize, awarded by the British Vacuum Council.
A cloaking device is a hypothetical or fictional stealth technology that can cause objects, such as spaceships or individuals, to be partially or wholly invisible to parts of the electromagnetic (EM) spectrum. Fictional cloaking devices have been used as plot devices in various media for many years.
Invisibility is the state of an object that cannot be seen. An object in this state is said to be invisible. The phenomenon is studied by physics and perceptual psychology.
A metamaterial is a type of material engineered to have a property that is rarely observed in naturally occurring materials. They are made from assemblies of multiple elements fashioned from composite materials such as metals and plastics. These materials are usually arranged in repeating patterns, at scales that are smaller than the wavelengths of the phenomena they influence. Metamaterials derive their properties not from the properties of the base materials, but from their newly designed structures. Their precise shape, geometry, size, orientation and arrangement gives them their smart properties capable of manipulating electromagnetic waves: by blocking, absorbing, enhancing, or bending waves, to achieve benefits that go beyond what is possible with conventional materials.
Negative refraction is the electromagnetic phenomenon where light rays become refracted at an interface that is opposite to their more commonly observed positive refractive properties. Negative refraction can be obtained by using a metamaterial which has been designed to achieve a negative value for (electric) permittivity (ε) and (magnetic) permeability (μ); in such cases the material can be assigned a negative refractive index. Such materials are sometimes called "double negative" materials.
A superlens, or super lens, is a lens which uses metamaterials to go beyond the diffraction limit. The diffraction limit is a feature of conventional lenses and microscopes that limits the fineness of their resolution depending on the illumination wavelength and the numerical aperture (NA) of the objective lens. Many lens designs have been proposed that go beyond the diffraction limit in some way, but constraints and obstacles face each of them.
Extraordinary optical transmission (EOT) is the phenomenon of greatly enhanced transmission of light through a subwavelength aperture in an otherwise opaque metallic film which has been patterned with a regularly repeating periodic structure. Generally when light of a certain wavelength falls on a subwavelength aperture, it is diffracted isotropically in all directions evenly, with minimal far-field transmission. This is the understanding from classical aperture theory as described by Bethe. In EOT however, the regularly repeating structure enables much higher transmission efficiency to occur, up to several orders of magnitude greater than that predicted by classical aperture theory. It was first described in 1998.
A METATOY is a sheet, formed by a two-dimensional array of small, telescopic optical components, that switches the path of transmitted light rays. METATOY is an acronym for "metamaterial for rays", representing a number of analogies with metamaterials; METATOYs even satisfy a few definitions of metamaterials, but are certainly not metamaterials in the usual sense. When seen from a distance, the view through each individual telescopic optical component acts as one pixel of the view through the METATOY as a whole. In the simplest case, the individual optical components are all identical; the METATOY then behaves like a homogeneous, but pixellated, window that can have very unusual optical properties.
Negative-index metamaterial or negative-index material (NIM) is a metamaterial whose refractive index for an electromagnetic wave has a negative value over some frequency range.
A terahertz metamaterial is a class of composite metamaterials designed to interact at terahertz (THz) frequencies. The terahertz frequency range used in materials research is usually defined as 0.1 to 10 THz.
An acoustic metamaterial, sonic crystal, or phononic crystal is a material designed to control, direct, and manipulate sound waves or phonons in gases, liquids, and solids. Sound wave control is accomplished through manipulating parameters such as the bulk modulus β, density ρ, and chirality. They can be engineered to either transmit, or trap and amplify sound waves at certain frequencies. In the latter case, the material is an acoustic resonator.
A photonic metamaterial (PM), also known as an optical metamaterial, is a type of electromagnetic metamaterial, that interacts with light, covering terahertz (THz), infrared (IR) or visible wavelengths. The materials employ a periodic, cellular structure.
A nonlinear metamaterial is an artificially constructed material that can exhibit properties not yet found in nature. Its response to electromagnetic radiation can be characterized by its permittivity and material permeability. The product of the permittivity and permeability results in the refractive index. Unlike natural materials, nonlinear metamaterials can produce a negative refractive index. These can also produce a more pronounced nonlinear response than naturally occurring materials.
Metamaterial cloaking is the usage of metamaterials in an invisibility cloak. This is accomplished by manipulating the paths traversed by light through a novel optical material. Metamaterials direct and control the propagation and transmission of specified parts of the light spectrum and demonstrate the potential to render an object seemingly invisible. Metamaterial cloaking, based on transformation optics, describes the process of shielding something from view by controlling electromagnetic radiation. Objects in the defined location are still present, but incident waves are guided around them without being affected by the object itself.
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.
Theories of cloaking discusses various theories based on science and research, for producing an electromagnetic cloaking device. Theories presented employ transformation optics, event cloaking, dipolar scattering cancellation, tunneling light transmittance, sensors and active sources, and acoustic cloaking.
Transformation optics is a branch of optics which applies metamaterials to produce spatial variations, derived from coordinate transformations, which can direct chosen bandwidths of electromagnetic radiation. This can allow for the construction of new composite artificial devices, which probably could not exist without metamaterials and coordinate transformation. Computing power that became available in the late 1990s enables prescribed quantitative values for the permittivity and permeability, the constitutive parameters, which produce localized spatial variations. The aggregate value of all the constitutive parameters produces an effective value, which yields the intended or desired results.
A plasmonic metamaterial is a metamaterial that uses surface plasmons to achieve optical properties not seen in nature. Plasmons are produced from the interaction of light with metal-dielectric materials. Under specific conditions, the incident light couples with the surface plasmons to create self-sustaining, propagating electromagnetic waves known as surface plasmon polaritons (SPPs). Once launched, the SPPs ripple along the metal-dielectric interface. Compared with the incident light, the SPPs can be much shorter in wavelength.
Illusion optics is an electromagnetic theory that can change the optical appearance of an object to be exactly like that of another virtual object, i.e. an illusion, such as turning the look of an apple into that of a banana. Invisibility is a special case of illusion optics, which turns objects into illusions of free space. The concept and numerical proof of illusion optics was proposed in 2009 based on transformation optics in the field of metamaterials. It is a scientific disproof of the idiom 'Seeing is Believing'.
Ji-Ping Huang is a Chinese theoretical physicist known for his invention of the concept of diffusion metamaterials.
Diffusion metamaterials are a subset of the metamaterial family, which primarily comprises thermal metamaterials, particle diffusion metamaterials, and plasma diffusion metamaterials. Currently, thermal metamaterials play a pivotal role within the realm of diffusion metamaterials. The applications of diffusion metamaterials span various fields, including heat management, chemical sensing, and plasma control, offering capabilities that surpass those of traditional materials and devices.
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