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Abstract Electromagnetic metamaterials, which are a major type of artificially engineered materials, have boosted the development of optical and photonic devices due to their unprecedented and controllable effective properties, including electric permittivity and magnetic permeability. Metamaterials consist of arrays of subwavelength unit cells, which are also known as meta-atoms. Importantly, the effective properties of metamaterials are mainly determined by the geometry of the constituting subwavelength unit cells rather than their chemical composition, enabling versatile designs of their electromagnetic properties. Recent research has mainly focused on reconfigurable, tunable, and nonlinear metamaterials towards the development of metamaterial devices, namely, metadevices, via integrating actuation mechanisms and quantum materials with meta-atoms. Microelectromechanical systems (MEMS), or microsystems, provide powerful platforms for the manipulation of the effective properties of metamaterials and the integration of abundant functions with metamaterials. In this review, we will introduce the fundamentals of metamaterials, approaches to integrate MEMS with metamaterials, functional metadevices from the synergy, and outlooks for metamaterial-enabled photonic devices.
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Gravitomagnetic Dipole Moment of Gravitational Unit Cells
It is proposed that gravitational meta-atom unit cells with gravitomagnetic moments could exhibit gravitomagnetic permeability, analogous to the magnetic permeability of materials comprised of atoms with magnetic moments. Recently, a gravitoelectromagnetic (GEM) framework was proposed to explore the possibility of a Veselago-inspired approach to gravitational metamaterials. The prospect of gravitational metamaterials motivates the consideration of candidate gravitational unit cells or gravitational meta-atoms. Although mass serves as a monopole source of a gravitoelectric field similar to positive charge, negative mass would be needed to create a gravitational analog of an electric dipole. However, moving mass is analogous to electric current, and can lead to a gravitomagnetic dipole moment analogous to magnetic dipole moments of magnetic materials and atoms. In this paper, GEM field approximations to general relativity are used to find the gravitomagnetic dipole moment of different rotating systems, ranging in scale from meters to astronomical size.
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- Award ID(s):
- 1731675
- PAR ID:
- 10318218
- Date Published:
- Journal Name:
- 2020 Fourteenth International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials)
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/Metamaterials49557.2020.9285033
