Tuesday, January 21, 2014

Metamaterials

Metamaterials The new metamaterial world has liberated theorists to dream and challenged experimentalists to make them happen. exceptt end Pendry Metamaterials argon artificially social systemd materials that have properties that cannot be arrange in nature. The literal definition comes from the Greek meta, meaning beyond. From the technological and engineering viewpoint, the interest in metamaterials is based on the possibility of designing devices and systems with new properties or functionalities, able to envision surface up new fields of application or to cleanse existing ones. There argon several types of metamaterials, severally with contrastive applications. The first type of metamaterials that will be discussed atomic number 18 photonic metamaterials, which are designed to interact with opthalmic frequencies. These structures are make from at least two different materials, usually involving some(prenominal) metals and dielectrics. They are normally periodi c, with the period being small compared to the optical wavelength. Therefore, the excess optical properties do not arise from photonic bandgaps, but instead from an interaction which is more similar to that of atoms or ion in a normal solid medium. Figure 1. Band structure in insulators or semiconductors A bandgap is an energy range in a solid where no electron states can exist. In other(a) words, the bandgap is the difference between the bottom of the conduction band and the drop off of the valence band (Figure 1) in insulators and semiconductors. This is equal to the energy hire to free an outer shell electron from its orbit more or less the nucleus. The next type of metamaterial, which is the most studied one, is an electromagnetic metamaterial. introductory to understanding electromagnetic metamaterials, a brief explanation of the electromagnetic spectrum must be presented. Figure 2: The electromagnetic spectrum The electromagnetic spectrum is the range of fr equencies existing due to electromagnetic ra! diation, ranging from short wavelengths such(prenominal) as gamma rays to...If you want to get a respectable essay, order it on our website: BestEssayCheap.com

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