Exceptional Points in the Flatland: A Non-Hermitian Line-Wave Scenario
arXiv:2106.04956 · doi:10.1103/PhysRevApplied.15.064067
Abstract
Line waves are recently discovered wave entities that are localized along two directions, and therefore can be viewed as the one-dimensional counterpart of surface waves. These waves can be supported at discontinuities of the surface reactance and/or resistance of low-dimensional materials such as metasurfaces or graphene. Here, a broader class of non-Hermitian surface-impedance junctions is studied that can support coupled line waves, and allows investigating different one-dimensional waveguiding mechanisms in a unified framework. It is theoretically demonstrated that, under parity-time-symmetry conditions, exceptional points can occur in a truly flat-optics scenario, hence endowing these waveguiding systems with the attractive features of both line-wave and exceptional-point physics, and shedding further light on the phase transitions existing in these systems. It is also shown that the required surface-impedance parameters are compatible with those attainable with typical models of photoexcited graphene metasurfaces at terahertz frequencies. Besides providing additional understanding in the physics of line waves, which is still in its infancy, these results pave the way to intriguing developments in the largely unexplored field of non-Hermitian flat optics, with possible applications ranging from sensing to lasing and on-chip optical signal processing.
arXiv comment25 pages; 12 figures. Minor revisions in the title and text
References in corpus (24)
- Array Programming with NumPy
- Real Spectra in Non-Hermitian Hamiltonians Having PT Symmetry
- Dyadic Green's Functions and Guided Surface Waves for a Surface Conductivity Model of Graphene
- Nonreciprocal light transmission in parity-time-symmetric whispering-gallery microcavities
- Chiral Quantum Optics
- The physics of exceptional points
- Dynamically encircling exceptional points in a waveguide: asymmetric mode switching from the breakdown of adiabaticity
- Simple and accurate analytical model of planar grids and high-impedance surfaces comprising metal strips or patches
- Spawning rings of exceptional points out of Dirac cones
- Dirac cones reshaped by interaction effects in suspended graphene
- Conservation relations and anisotropic transmission resonances in one-dimensional PT-symmetric photonic heterostructures
- Dynamically encircling exceptional points: Exact evolution and polarization state conversion
- Spectral singularities and Bragg scattering in complex crystals
- Light stops at exceptional points
- PT-Symmetric Sinusoidal Optical Lattices at the Symmetry-Breaking Threshold
- Guiding waves along an infinitesimal line between impedance surfaces
- Quasi PT-symmetry in passive photonic lattices
- Topological Wave-Guiding Near an Exceptional Point: Defect-Immune, Slow-Light, Loss-Immune Propagation
- Causality and phase transitions in PT-symmetrical optical systems
- Ultrafast Carrier Recombination and Generation Rates for Plasmon Emission and Absorption in Graphene
- Tuning Photoinduced Terahertz Conductivity in Monolayer Graphene: Optical Pump Terahertz Probe Spectroscopy
- Exceptional points of degeneracy and -symmetry in photonic coupled chains of scatterers
- Dissipation-induced topological transitions in continuous Weyl materials
- Emulating exceptional-point encirclements using imperfect (leaky) photonic components