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Metamaterials

Metamaterials are artificially engineered materials with unique electromagnetic properties not found in nature, enabling applications like superlenses, absorbers, cloaking technologies, and communication devices. They exhibit phenomena such as negative refractive index, reverse Doppler effect, and enable the construction of devices to detect biological or chemical agents. The potential applications span various fields, including optics, wireless communications, and defense technology.

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Meta-Materials Presented by- 1. Tanmay Padwal 19CHE220 2. Dhiraj Sutar 19CHE207
Introduction Meta (from the Greek word μετά ) - beyond. Metamaterials are new artificial materials with unusual electromagnetic properties that are not found in naturally occurring materials.[1] Materials which extract their properties from their structure rather than materials of which the are composed of[2]
n= Index of refraction c= speed of light in vacuum v= speed of light in medium
Negative refractive index
1.Concept of Metamaterials was first introduced in 1968 by soviet physicist V.G. Veselago. He said “materials with both negative permittivity and negative permeability are theoretically possible”.[3] 2.John Pendry identified a practical way to make metamaterials. He proposed his design of periodically arranged Thin-Wire (TW) structure that depicts the negative value of effective permittivity. [2] V.G. Veselago History
Negative refractive index
Classification of materials
Double positive (DPS) materials The materials which have both permittivity & permeability greater than zero (ε > 0, μ > 0) are called as double positive (DPS) materials. Most occurring media (e.g. dielectrics) fall under this designation. The forward propagation of wave takes place in first quadrant. It follows Right hand thumb rule for direction of propagation of wave
Epsilon negative (ENG) materials If a material has permittivity less than zero and permeability greater than zero (ε < 0, μ > 0) it is called as epsilon negative (ENG) material. Eg. Plasmas
Mu negative (MNG) materials If a material has permittivity greater than zero & permeability less than zero (ε > 0, μ < 0) it is called as mu negative (MNG) material. This also support evanescent waves.
Double negative (DNG) materials The third quadrant ε<0, μ < 0 represents materials, also called left handed materials. It follows the left hand rule because propagation of wave takes place in backward direction in this medium. Due to negative ε and negative μ, the refractive index of the medium is calculated to be negative. Thus termed as NIM (negative index materials).
Split ring resonators
Special effects shown by Metamaterials 1. Reverse doppler effect 2. Reverse Cherenkov effect
Reverse doppler Another strange property of metamaterials is the reverse Doppler effect. It makes a train-whistle sound higher in pitch as it approaches and lower in pitch as it recedes. The possible application for such phenomenon is in mobile wireless communication and is still under investigation.
Reverse Cherenkov effect Charged particle passing through a medium emits light from a cone behind the particle rather than in front of it as in “normal” materials. Cherenkov radiation occurs when a charged particle moves in a material with a speed faster than light. In particle physics, one possible application is constructing a Cherenkov detector to identify charged particles of various velocities.
Reverse chernkov effect
Metamaterials as combination of different material properties 1. With conventional materials, we are stuck with the properties of materials being same everywhere. 2. With metamaterials, we can put different material properties in each of the squares shown in the figure. 3. The materials are arranged in repeating patterns, at scales that are smaller than thewavelengths
Applications of Metamaterials Superlens Absorber Cloaking WMD detectors Flying Antennas
Metamaterials in optics : “Super” lens John B. Pendry, a physicist at the Imperial College London, has claimed that lens made of metamaterials could focus light for objects less than wavelength λ in size to a geometric point. All lens utilizing natural materials known today cannot focus light onto an area smaller than the square wavelength of the light used to examine it (the diffraction limit). Sub-wavelength resolution, or focusing beyond the diffraction limit, is possible with a perfect, flat lens made up of metamaterials. In optics, every lens made has been limited by the wavelength of the light it uses to focus until now. With metamaterials, a “super” lens that can focus on features smaller than the wavelength of the light itself should be possible. The electrical permittivity ε (response to an electric field) and the magnetic permeability µ (response to a magnetic field) are the main determinants of a material’s response to electromagnetic (EM) waves
Super resolution imaging
The supermicroscope
Metamaterials as absorber ❖ Research is being done for the design of thin electromagnetic absorbers. 11.5GHz the experimental absorptivity of 88% (Landy 2008) ❖ This absorbers can operate in microwave , terahertz and even in visible frequencies. ❖ Electromagnetic wave absorber: A device which absorb all incident radiation at the operating frequency. ❖ Metamaterials have allowed for the development of a perfect absorber
Metamaterial absorber A single unit cell of the absorber consisted of two distinct metallic elements as shown in fig. Electric coupling was supplied by the electric ring resonator (ERR) shown in fig. (a). This element consisted of two standard split ring resonator connected by the inductive ring parallel to the split wire. (a) ERR, (b) cut wire, (c) axis shown with propagation direction
Metamaterial Cloaking ❖ 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. ❖ Objects in the defined location are still present, but incident waves are guided around them without being affected by the object itself
Cloaking effect
Applications : Invisible submarines To make submarine invisible to enemy sonar, it bends sound around it and this program is funded by Russian Naval Research. The findings showed that the waves reflected from the metamaterial matched the phase of the reflected wave of the surface. Additionally, the amplitude of the reflected wave from the cloaked object decreased slightly.
Metamaterials as Weapon of Mass Destruction Detectors 1. Army researchers are using metamaterials to build biological- and chemical-agent detectors. 2. Metallic nanostructures in metamaterials react electromagnetically to incoming molecules, revealing their identities through a variety of responses. 3. This method can detect single molecules, which could be of great use for passenger or cargo screening. 4. Availability: Possibly as little as five years for a working prototype.
Metamaterials for flying 1. A proposed scheme for generating torus-shaped light pulses called flying doughnuts utilizes a metamaterial “sprinkled” with tiny resonators in a concentric ring pattern. 2. Electromagnetic waves are typically transverse, which means their electric and magnetic fields point perpendicularly to the direction of wave propagation. 3. Certain electromagnetic waveforms have longitudinal field components that are parallel to the propagation direction. 4. One example is the flying electromagnetic doughnut, whose fields wrap around in a torus pattern. Such pulses could potentially transfer information, accelerate particles, or perform spectroscopy
Flying Doughnut
Metamaterials as Antenna 1. An antenna is an arrangement of two or more conductors usually called elements. 2. At transmitter of antenna, an alternating current is created in the elements which radiate electromagnetic field. 3. In reception, reverse occurs. 4. Advantages: Small size, Increased directivity , Step up radiated power by impedance matching.
Applications of MM antennas 1. High speed Wireless communication (Wifi) 2. Space communications 3. GPS 4. Satellites 5. Space vehicle navigation
Application-Super cellphones 1. Although they measure just a few millimeters long and are as flat as paper, the new multiband antennas could double the range, reliability and battery life of cellular phones, Wi-Fi routers and wireless modems. 2. Availability: Already for sale, but the quality is expected to steadily improve over the next five years. 3. LG chocolate BL 40 is using metamaterial antennas.
References 1. A brief intro to metamaterials IEEE Author : R.S. Kshetrimayum 2. Negative refraction ,Contemporary Physics: J. B. PENDRY 3. A Review of Metamaterials and its Applications:Gurwinder Singh, Rajni, Anupma Marwaha 4. ,Metamaterials: Fundamentals and Applications in the MicrowaveandOpticalRegimes By GEORGE V. ELEFTHERIADES 5. A Review of Metamaterials and its Applications Gurwinder Singh , Rajni, Anupma Marwaha 6. The century of metamaterials to cite this article: Sergei Tretyakov 7. Hybridization effect in coupled metamaterialsHui Liu, Tao LI, Shu-ming Wang and Shi-ning Zhu 8. A Study of Significance of Metamaterial in Antenna Array Elements DesignNeha Singh, Kamal Kishor Choure, Amandeep Kochar 9. Metamaterial Antennas and Applications- A Review Jaget Singh 10. Metamaterials: Characteristics, Process and Applications Kaushal Gangwar , Dr. Paras and Dr. R.P.S. Gangwar 11. A review paper on Techniques and Design for metamaterialsRekha Chahar , Neelam singh
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