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Vortical Reflection and Spiraling Fermi Arcs with Weyl Metamaterials
Hua Cheng1,2, Wenlong Gao1, Yangang Bi1,3
1School of Physics & Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom.
Physical Review Letters
|September 11, 2020
Summary
Researchers observed helical phase distributions in photonic Weyl metamaterials, enabling direct observation of electron momentum and creating spiraling Fermi arcs for optical angular momentum manipulation.
Area of Science:
- Condensed matter physics
- Metamaterials science
- Photonics
Background:
- Weyl semimetals exhibit unique electronic properties like chiral zero modes.
- Electrical conductance measurements in Weyl semimetals cannot resolve electron momentum.
- Direct observation of phase singularities in scattering matrices is challenging.
Purpose of the Study:
- To experimentally demonstrate a helical phase distribution in the scattering matrix of electromagnetic waves.
- To investigate the formation of spiraling Fermi arcs in a photonic Weyl system.
- To establish a new platform for manipulating optical angular momenta.
Main Methods:
- Utilizing a photonic Weyl metamaterial to study electromagnetic wave scattering.
- Measuring the angle (momentum) resolved scattering matrix.
- Creating an air gap between the Weyl metamaterial and a metal plate.
Main Results:
- A helical phase distribution was experimentally demonstrated in the scattering matrix.
- Spiraling Fermi arcs were observed in the air gap.
- The system demonstrated alignment-free angular vortical reflection.
Conclusions:
- The study provides direct observation of phase singularities in a photonic system.
- The findings establish a novel platform for optical angular momentum manipulation using photonic Weyl systems.
- This work opens new avenues for exploring topological phenomena in metamaterials.
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