Tunable Metamaterials
Introduction
Tunable metamaterials are artificial materials engineered to have properties that may not be found in nature. They are assemblies of multiple individual elements fashioned from conventional microscopic materials such as metals or plastics, but the materials are usually arranged in periodic patterns. Tunable metamaterials derive their properties not from the properties of the base materials, but from their newly-invented structures. Their precise shape, geometry, size, orientation and arrangement can affect the waves of light or sound in an unconventional manner, creating material properties which are unachievable with conventional materials.
History and Development
The concept of metamaterials dates back to the early 20th century, but the term 'metamaterial' was not coined until 1999 by Rodney Allam, a physicist at Imperial College London. The development of tunable metamaterials has been a significant advancement in the field of materials science, opening up new possibilities for manipulating electromagnetic waves, sound waves, and mechanical vibrations.
Structure and Design
Tunable metamaterials are typically composed of arrays of sub-wavelength resonators. The resonators can be made from various materials, including metals, dielectrics, and semiconductors. The design and arrangement of these resonators determine the overall properties of the metamaterial. The resonators can be designed to interact with specific frequencies of electromagnetic or acoustic waves, allowing the metamaterial to exhibit unique properties such as negative refraction or cloaking.
Properties and Applications
Tunable metamaterials exhibit a wide range of unique properties that are not found in natural materials. These properties can be manipulated by changing the physical parameters of the metamaterial, such as the shape, size, and arrangement of the resonators. This allows for a high degree of control over the interaction between the metamaterial and electromagnetic or acoustic waves.
One of the most well-known properties of metamaterials is negative refraction, which can be used to create superlenses that surpass the diffraction limit of conventional lenses. Other applications of tunable metamaterials include cloaking devices, antennas, and sensors.
Future Perspectives
The field of tunable metamaterials is still in its early stages, and there is much potential for future research and development. As our understanding of these materials continues to grow, it is likely that we will see an increasing number of applications for these materials in various fields, including telecommunications, medicine, and defense.