Abstract:
The present disclosure is directed to systems for tuning nanocube plasmonic resonators and methods for forming tunable plasmonic resonators. A tunable plasmonic resonator system can include a substrate and a nanostructure positioned on a surface of the substrate. The substrate can include a semiconductor material having a carrier density distribution. A junction can be formed between the nanostructure and the substrate forming a Schottky junction. Changing the carrier density distribution of the semiconductor material can change a plasmonic response of the plasmonic resonator.
Abstract:
The present disclosure provides systems and methods associated with mode conversion for electromagnetic field modification. A mode converting structure (holographic metamaterial) is formed with a distribution of dielectric constants chosen to convert an input electromagnetic field pattern from a first mode to a second mode to attain a target electromagnetic field pattern (near or far) that is different from the input electromagnetic field pattern. A solution to a holographic equation provides a sufficiently accurate approximation of a distribution of dielectric constants that can be used in conjunction with an electromagnetic radiation device with a known output field pattern to attain a target field pattern. A voxel-based discretization of the distribution of dielectric constants can be used to generate the mode converting structure and/or to facilitate the optimization algorithms. One or more optimization algorithms can be used to improve the efficiency of the mode conversion.
Abstract:
The present disclosure provides systems and methods associated with mode conversion for electromagnetic field modification. A mode converting structure (holographic metamaterial) is formed with a distribution of dielectric constants chosen to convert an electromagnetic radiation pattern from a first mode to a second mode to attain a target electromagnetic radiation pattern that is different from the input electromagnetic radiation pattern. A solution to a holographic equation provides a sufficiently accurate approximation of a distribution of dielectric constants that can be used to form a mode converting device for use with one or more transmission lines, such as waveguides. One or more optimization algorithms can be used to improve the efficiency of the mode conversion.
Abstract:
Methods and system for performing magnetic induction tomography imaging of an object are provided. An apparatus includes an array of unit cells and a control circuit coupled to the array of unit cells. The array of unit cells can generate a first magnetic field using an excitation pattern in the direction of a target object and sense a second magnetic field induced in the target object by the first magnetic field. The control circuit can determine a minimum of the first magnetic field. The minimum may correspond to a higher conductivity region of the target object. The control circuit can adjust the excitation pattern based on the higher conductivity region of the target object.
Abstract:
An apparatus having reduced phononic coupling between a graphene monolayer and a substrate is provided. The apparatus includes an aerogel substrate and a monolayer of graphene coupled to the aerogel substrate.
Abstract:
An apparatus for reducing electromagnetic scattering includes a first component having a plurality of curved segments, each including a first reflective material, and together forming an enclosed cavity; and a second component having a plurality of flat or cylindrically-curved segments, each comprising a second reflective material. The second component is positioned external to the cavity.
Abstract:
Described embodiments include a system, apparatus, and method. An apparatus includes an assemblage of artificially structured electromagnetic unit cells. The assemblage of artificially structured electromagnetic unit cells includes a first artificially structured electromagnetic unit cell configured to transform incident radiofrequency electromagnetic waves into a radiofrequency magnetic field B perpendicular to the plane of the assemblage. The assemblage of artificially structured electromagnetic unit cells includes a second artificially structured electromagnetic unit cell configured to transform the incident radiofrequency electromagnetic waves into an electric field E counteracting a non-vanishing electric field component generated by the first artificially structured electromagnetic unit cell.
Abstract:
Described embodiments include an apparatus, and a method. An apparatus includes an array of at least two artificially structured electromagnetic unit cells. The at least two artificially structured electromagnetic unit cells are configured to generate a pulse of radiofrequency magnetic field B1 orientated transverse to the quasistatic magnetic field B0 parallel to the z-axis of the bore of a MRI or NMR device by transforming an incident pulse of radiofrequency electromagnetic waves. The generated pulse having magnetic field intensity sufficient to excite a detectable magnetic resonance in magnetically active nuclei located within at least a portion of an examination region located within the bore. The apparatus includes a radiofrequency electromagnetic wave conducting structure configured to distribute a received pulse of radiofrequency electromagnetic waves as an incident pulse of radiofrequency electromagnetic waves to the at least two artificially structured electromagnetic unit cells.
Abstract:
According to various embodiments, an array of elements forms an artificially-structured material. The artificially-structured material can also include an array of tuning mechanisms included as part of the array of elements that are configured to change material properties of the artificially-structured material on a per-element basis. The tuning mechanisms can change the material properties of the artificially-structured material by changing operational properties of the elements in the array of elements on a per-element basis based on one or a combination of stimuli detected by sensors included in the array of tuning mechanisms, programmable circuit modules included as part of the array of tuning mechanisms, data stored at individual data stores included as part of the array of tuning mechanisms, and communications transmitted through interconnects included as part of the array of elements.