Transformation optics

Quantum mechanics

Slot antenna

Engineering

Dirac (video compression format)

Telecommunications

Metamaterial

Neutrino

Computer science

Antenna (radio)

Directional antenna

Photonics

Physics

Mathematics

Optics

Isotropy

Metamaterial antenna

Combinatorics

Topology (electrical circuits)

Electrical engineering

Light Science & Applications

Metamaterials with a Dirac-like cone dispersion at the center of the Brillouin zone behave like an isotropic and impedance-matched zero refractive index material at the Dirac-point frequency. Such metamaterials can be realized in the form of either bulk metamaterials with efficient coupling to free-space light or on-chip metamaterials that are efficiently coupled to integrated photonic circuits. These materials enable the interactions of a spatially uniform electromagnetic mode with matter over a large area in arbitrary shapes. This unique optical property paves the way for many applications, including arbitrarily shaped high-transmission waveguides, nonlinear enhancement, and phase mismatch-free nonlinear signal generation, and collective emission of many emitters. This review summarizes the Dirac-like cone-based zero-index metamaterials’ fundamental physics, design, experimental realizations, and potential applications.

Dirac-like cone-based electromagnetic zero-index metamaterials