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Title: Spawning rings of exceptional points out of Dirac cones

Journal Article · · Nature (London)
DOI:https://doi.org/10.1038/nature14889· OSTI ID:1371039
 [1];  [2];  [3];  [1];  [1];  [4];  [5];  [1];  [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Research Lab. of Electronics
  2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Research Lab. of Electronics; Yale Univ., New Haven, CT (United States). Dept. of Applied Physics
  3. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Research Lab. of Electronics; NEC Corporation, Tsukuba, Ibaraki (Japan). Smart Energy Research Lab.
  4. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Research Lab. of Electronics; Harvard Univ., Cambridge, MA (United States). Dept. of Physics
  5. DSO National Lab. (Singapore)

The Dirac cone underlies many unique electronic properties of graphene and topological insulators, and its band structure—two conical bands touching at a single point—has also been realized for photons in waveguide arrays, atoms in optical lattices, and through accidental degeneracy. Deformation of the Dirac cone often reveals intriguing properties; an example is the quantum Hall effect, where a constant magnetic field breaks the Dirac cone into isolated Landau levels. A seemingly unrelated phenomenon is the exceptional point, also known as the parity–time symmetry breaking point, where two resonances coincide in both their positions and widths. Exceptional points lead to counter-intuitive phenomena such as loss-induced transparency, unidirectional transmission or reflection, and lasers with reversed pump dependence or single-mode operation. Dirac cones and exceptional points are connected: it was theoretically suggested that certain non-Hermitian perturbations can deform a Dirac cone and spawn a ring of exceptional points. Here we experimentally demonstrate such an ‘exceptional ring’ in a photonic crystal slab. Angle-resolved reflection measurements of the photonic crystal slab reveal that the peaks of reflectivity follow the conical band structure of a Dirac cone resulting from accidental degeneracy, whereas the complex eigenvalues of the system are deformed into a two-dimensional flat band enclosed by an exceptional ring. This deformation arises from the dissimilar radiation rates of dipole and quadrupole resonances, which play a role analogous to the loss and gain in parity–time symmetric systems. In this study, our results indicate that the radiation existing in any open system can fundamentally alter its physical properties in ways previously expected only in the presence of material loss and gain.

Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
SC0001299; FG02-09ER46577
OSTI ID:
1371039
Journal Information:
Nature (London), Vol. 525, Issue 7569; Related Information: S3TEC partners with Massachusetts Institute of Technology (lead); Boston College; Oak Ridge National Laboratory; Rensselaer Polytechnic Institute; ISSN 0028-0836
Publisher:
Nature Publishing GroupCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 527 works
Citation information provided by
Web of Science

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Nonreciprocal Transmission in Nonlinear PT‐Symmetric Metamaterials Using Epsilon‐Near‐Zero Media Doped with Defects journal September 2019
Topology Optimization of Photonic and Phononic Crystals and Metamaterials: A Review journal April 2019
Two-Dimensional Boron Hydride Sheets: High Stability, Massless Dirac Fermions, and Excellent Mechanical Properties journal July 2016
Topologically Protected Doubling of Tilted Dirac Fermions in Two Dimensions journal January 2019
Strong absorption near exceptional points in plasmonic waveguide arrays journal August 2018
Topological gapless matters in three-dimensional ultracold atomic gases journal April 2019
Topological photonic crystals: a review journal January 2020
Topological energy transfer in an optomechanical system with exceptional points journal July 2016
Enhanced sensitivity at higher-order exceptional points journal August 2017
Exceptional points enhance sensing in an optical microcavity journal August 2017
Experimental observation of optical Weyl points and Fermi arc-like surface states journal March 2017
Non-Hermitian physics and PT symmetry journal January 2018
Dynamically encircling an exceptional point in anti-parity-time symmetric systems: asymmetric mode switching for symmetry-broken modes journal October 2019
Extracting more light for vertical emission: high power continuous wave operation of 1.3-μm quantum-dot photonic-crystal surface-emitting laser based on a flat band journal November 2019
Non-Hermitian photonics promises exceptional topology of light journal July 2018
Robust lasing modes in coupled colloidal quantum dot microdisk pairs using a non-Hermitian exceptional point journal February 2019
Optical vector analysis with attometer resolution, 90-dB dynamic range and THz bandwidth journal November 2019
Parity–time symmetry and exceptional points in photonics journal April 2019
Non-Hermitian photonics based on parity–time symmetry journal November 2017
Inverse design in nanophotonics journal October 2018
Quantum state tomography across the exceptional point in a single dissipative qubit journal October 2019
Manipulation of Dirac Cones in Mechanical Graphene journal December 2015
A theoretical insight into a feasible strategy for the fabrication of borophane journal January 2018
Quantum capacitance of CuS:Ce 3+ quantum dots as high-performing supercapacitor electrodes journal January 2018
Asymmetric diffraction based on a passive parity-time grating journal September 2016
The boomerang effect in electron-hydrogen molecule scattering as determined by time-dependent calculations journal May 2017
Metamaterial, plasmonic and nanophotonic devices journal February 2017
Manipulating the flow of light using Dirac-cone zero-index metamaterials journal November 2018
Parity–time symmetric photonics journal January 2018
Collectively induced exceptional points of quantum emitters coupled to nanoparticle surface plasmons journal January 2020
State flip at exceptional points in atomic spectra journal January 2016
Anomalous parity-time–symmetry transition away from an exceptional point journal July 2016
Exceptional points and symmetry recovery in a two-state system journal August 2017
Cross-polarization mode coupling and exceptional points in photonic crystal slabs journal January 2018
Piecewise adiabatic following in non-Hermitian cycling journal May 2018
Invisibility on demand based on a generalized Hilbert transform journal July 2018
High-order exceptional points in ultracold Bose gases journal January 2019
Interplay of non-Hermitian skin effects and Anderson localization in nonreciprocal quasiperiodic lattices journal August 2019
Controlling photonic spin Hall effect via exceptional points journal September 2019
Inversion symmetric non-Hermitian Chern insulator journal October 2019
Exceptional concentric rings in a non-Hermitian bilayer photonic system journal October 2019
PT -symmetric non-Hermitian Dirac semimetals journal December 2019
Hybrid exceptional point created from type-III Dirac point journal January 2020
Coalescence of exceptional points and phase diagrams for one-dimensional P T -symmetric photonic crystals journal December 2015
Disorder-driven exceptional lines and Fermi ribbons in tilted nodal-line semimetals journal January 2019
Topological exceptional surfaces in non-Hermitian systems with parity-time and parity-particle-hole symmetries journal January 2019
Non-Hermitian nodal-line semimetals with an anomalous bulk-boundary correspondence journal February 2019
Exceptional points and spectral singularities in active epsilon-near-zero plasmonic waveguides journal February 2019
Symmetry protected topological phases characterized by isolated exceptional points journal April 2019
Topology and exceptional points of massive Dirac models with generic non-Hermitian perturbations journal June 2019
Enhanced Spontaneous Emission at Third-Order Dirac Exceptional Points in Inverse-Designed Photonic Crystals journal August 2016
Experimental Demonstration of an Anisotropic Exceptional Point journal August 2018
Simultaneous Observation of a Topological Edge State and Exceptional Point in an Open and Non-Hermitian Acoustic System journal September 2018
Topological Phase Transition Driven by Infinitesimal Instability: Majorana Fermions in Non-Hermitian Spintronics journal August 2019
Experimental Observation of an Exceptional Surface in Synthetic Dimensions with Magnon Polaritons journal December 2019
Reservoir-Mediated Quantum Correlations in Non-Hermitian Optical System journal January 2020
Transition from Dirac points to exceptional points in anisotropic waveguides journal October 2019
Observation of bulk Fermi arc and polarization half charge from paired exceptional points journal January 2018
Exceptional points in optics and photonics journal January 2019
Topological states of non-Hermitian systems journal October 2018
Symmetry-engineered waveguide dispersion in $ {\cal P}{\cal T} $PT symmetric photonic crystal waveguides journal December 2019
Spawning a ring of exceptional points from a metamaterial journal January 2017
Photonic crystals for controlling strong coupling in van der Waals materials journal January 2019
Exceptional points and photonic catastrophe journal January 2018
Chiral dynamics of exceptional points in weakly absorbing biaxial crystal journal January 2018
Exceptional surfaces in PT-symmetric non-Hermitian photonic systems journal January 2019
Non-Hermitian lattices with a flat band and polynomial power increase [Invited] journal January 2018
Two-Dimensional Boron Hydride Sheets: High Stability, Massless Dirac Fermions, and Excellent Mechanical Properties journal July 2016
Topologically Protected Doubling of Tilted Dirac Fermions in Two Dimensions journal February 2019
Direct observation of exceptional points in coupled photonic-crystal lasers with asymmetric optical gains journal December 2016
Topological unification of time-reversal and particle-hole symmetries in non-Hermitian physics journal January 2019
Arbitrary order exceptional point induced by photonic spin–orbit interaction in coupled resonators journal February 2019
Continuous transition between weak and ultrastrong coupling through exceptional points in carbon nanotube microcavity exciton–polaritons journal April 2018
Non-hermitian topology as a unifying framework for the Andreev versus Majorana states controversy journal October 2019
Temperature-controlled tunable underwater acoustic topological insulators journal June 2019
Tamm plasmon photonic crystals: From bandgap engineering to defect cavity journal October 2019
Chiral modes and directional lasing at exceptional points journal June 2016
Energy landscape and conical intersection points of the driven Rabi model journal November 2015
Unique band coalescence and exceptional points from two-dimensional photonic crystal waveguide journal April 2019
Quantum critical behavior influenced by measurement backaction in ultracold gases journal November 2016
Non-Hermiticity-induced flat band journal July 2017
Large Sagnac frequency splitting in a ring resonator operating at an exceptional point journal September 2017
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Non-Hermitian phase transition and eigenstate localization induced by asymmetric coupling journal June 2019
Generalized bulk-edge correspondence for non-Hermitian topological systems journal October 2019
Photonic emulation of two-dimensional materials with antiferromagnetic order journal December 2019
Effects of non-Hermitian perturbations on Weyl Hamiltonians with arbitrary topological charges journal February 2018
Symmetry-protected exceptional rings in two-dimensional correlated systems with chiral symmetry journal March 2019
Anisotropic exceptional points of arbitrary order journal June 2019
Incident Direction Independent Wave Propagation and Unidirectional Lasing journal August 2018
Hybrid Higher-Order Skin-Topological Modes in Nonreciprocal Systems journal July 2019
Non-Hermitian Skin Effect and Chiral Damping in Open Quantum Systems journal October 2019
Quantum Noise Theory of Exceptional Point Amplifying Sensors journal October 2019
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Direct imaging of isofrequency contours in photonic structures journal November 2016
Exceptional points for resonant states on parallel circular dielectric cylinders journal January 2019
On-chip all-dielectric fabrication-tolerant zero-index metamaterials journal January 2017
General theory of spontaneous emission near exceptional points journal January 2017
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Dark-state lasers: mode management using exceptional points journal January 2016
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Active topological photonics journal January 2020
Parity-time-symmetric quantum critical phenomena journal June 2017
Generalized Fano lineshapes reveal exceptional points in photonic molecules journal January 2018
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Angle-Resolved Thermal Emission Spectroscopy Characterization of Non-Hermitian Metacrystals journal January 2020
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Dynamically encircling exceptional points: Exact evolution and polarization state conversion text January 2017
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Symmetry protected topological phases characterized by isolated exceptional points text January 2017
Parity-Time Symmetry in Non-Hermitian Complex Optical Media text January 2018
Arbitrary order exceptional point induced by photonic spin-orbit interaction in coupled resonators text January 2018
Topological exceptional surfaces in non-Hermitian systems with parity-time and parity-particle-hole symmetries text January 2018
Exceptional points and spectral singularities in active epsilon-near-zero plasmonic waveguides text January 2018
Symmetry and Topology in Non-Hermitian Physics text January 2018
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Non-Hermitian skin effect and chiral damping in open quantum systems text January 2019
Exceptional rings protected by emergent symmetry for mechanical systems text January 2019
Non-Hermitian Topological Invariants in Real Space text January 2019
Topological Phase Transition Independent of System Non-Hermiticity text January 2019
Inversion symmetric non-Hermitian Chern insulator text January 2019
Non-Hermitian phase transition and eigenstate localization induced by asymmetric coupling text January 2019
Nonreciprocal Transmission in Nonlinear PT-Symmetric Metamaterials Using Epsilon-near-Zero Media Doped with Defects text January 2019
Realization of complex conjugate media using non-PT-symmetric photonic crystals text January 2019
Generalized bulk-edge correspondence for non-hermitian topological systems text January 2019
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