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Simulation, Fabrication and Characterization of THz Metamaterial Absorbers
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Herpin equivalence in temporal metamaterials.

Giuseppe Castaldi1, Massimo Moccia1, Nader Engheta2

  • 1Department of Engineering, Fields & Waves Lab, University of Sannio, Benevento, I-82100, Italy.

Nanophotonics (Berlin, Germany)
|December 5, 2024
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Summary

Herpin equivalence allows temporal metamaterials with symmetric, step-like parameter changes to be replaced by a single temporal slab. This simplifies the design of advanced optical materials like anti-reflection coatings and filters.

Keywords:
Herpin equivalencefiltersmetamaterialstime-varying

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Area of Science:

  • Physics
  • Materials Science
  • Electromagnetism

Background:

  • Temporal metamaterials offer unique electromagnetic properties through time-varying parameters.
  • Spatial multilayer concepts inspire new approaches in temporal material design.

Purpose of the Study:

  • Introduce Herpin equivalence for temporal metamaterials.
  • Develop a method for synthesizing arbitrary refractive indices in temporal slabs.
  • Provide new analytical tools for temporal metamaterial design.

Main Methods:

  • Analogy with spatial multilayers to define Herpin equivalence.
  • Mathematical replacement of temporal multisteps with equivalent temporal slabs.
  • Analysis of refractive index and travel-time for equivalent slabs.

Main Results:

  • Demonstrated that symmetric temporal multisteps are equivalent to a single temporal slab.
  • Showed this equivalence enables synthesis of arbitrary refractive indices.
  • Established a method distinct from the effective-medium approach.

Conclusions:

  • Herpin equivalence provides a powerful analytical tool for temporal metamaterials.
  • This approach simplifies the design of complex temporal structures.
  • Potential applications include advanced anti-reflection coatings and filters.