Topological insulator laser: Experiments

Bandres, Miguel A.; Wittek, Steffen; Harari, Gal; Parto, Midya; Ren, Jinhan; Segev, Mordechai; Christodoulides, Demetrios N.; Khajavikhan, Mercedeh

doi:10.1126/science.aar4005

Cited by 1,180 publications

(867 citation statements)

References 35 publications

Supporting

Mentioning

856

Contrasting

Unclassified

Order By: Relevance

“…The interest in non-Hermitian Hamiltonians was originally focused in  -symmetric Hamiltonians [23] as a generalization of quantum mechanics where the Hermiticity constraint could be removed while keeping a real spectra. Today, this has shifted to non-Hermitian Hamiltonians regarded as an effective description of, for example, open quantum systems [24,25], where the finite lifetime introduced by electronelectron or electron-phonon interactions [26][27][28], or disorder [29], is modeled through a non-Hermitian term, or in the physics of lasing [30][31][32][33][34]. An additional source of momentum in this field comes from the study of systems where the quantum mechanical description is used after mapping to a Schrödinger-like equation, as in systems with gain and loss (as found in optics and photonics [35][36][37][38]), surface Maxwell waves [39], and topoelectrical circuits [40,41].…”

Section: Introductionmentioning

confidence: 99%

Perspective on topological states of non-Hermitian lattices

Torres

2019

J. Phys. Mater.

134

View full text Add to dashboard Cite

The search of topological states in non-Hermitian systems has gained a strong momentum over the last two years climbing to the level of an emergent research front. In this perspective we give an overview with a focus on connecting this topic to others like Floquet systems. Furthermore, using a simple scattering picture we discuss an interpretation of concepts like the Hamiltonian's defectiveness, i.e. the lack of a full basis of eigenstates, crucial in many discussions of topological phases of non-Hermitian Hamiltonians.

show abstract

Section: Introductionmentioning

confidence: 99%

Perspective on topological states of non-Hermitian lattices

Torres

2019

J. Phys. Mater.

134

View full text Add to dashboard Cite

show abstract

“…Our proposal provides a realistic scheme to realize photonic topological corner states in photonic graphene. Moreover, it offers an accessible platform to study higherorder generalization of the topological insulator laser, which has been experimentally implemented in similar photonic crystal [53][54][55][56]. Topological corner modes show negative imaginary parts.…”

Section: Discussionmentioning

confidence: 99%

Wannier-type photonic higher-order topological corner states induced solely by gain and loss

Liu

Hou

2020

Phys. Rev. A

View full text Add to dashboard Cite

Photonic crystals have provided a controllable platform to examine excitingly new topological states in open systems. In this work, we reveal photonic topological corner states in a photonic graphene with mirror-symmetrically patterned gain and loss. Such a nontrivial Wannier-type higherorder topological phase is achieved through solely tuning on-site gain/loss strengthes, which leads to annihilation of the two valley Dirac cones at time-reversal-symmetric point, as the gain and loss change the effective tunneling between adjacent sites. We find that the symmetry-protected photonic corner modes exhibit purely imaginary energies and the role of Wannier center as topological invariant is illustrated. For experimental considerations, we also examine the topological interface states near a domain wall. Our work introduces an interesting platform for non-Hermiticity-induced photonic higher-order topological insulators, to which, with current experimental technologies, can be readily accessed.

show abstract

“…1(f)). Lasing from helical edge states have also been examined with 2D arrays of microring resonators [29] (Fig. 1(g)); such systems can be interpreted as pseudo quantum spin Hall systems and can leverage topological protection for the propagating optical modes even without TRS breaking.…”

Section: Introductionmentioning

confidence: 99%

Active topological photonics

et al. 2020

View full text Add to dashboard Cite

Topological photonics has emerged as a novel route to engineer the flow of light. Topologically-protected photonic edge modes, which are supported at the perimeters of topologically-nontrivial insulating bulk structures, have been of particular interest as they may enable low-loss optical waveguides immune to structural disorder. Very recently, there is a sharp rise of interest in introducing gain materials into such topological photonic structures, primarily aiming at revolutionizing semiconductor lasers with the aid of physical mechanisms existing in topological physics. Examples of remarkable realizations are topological lasers with unidirectional light output under time-reversal symmetry breaking and topologically-protected polariton and micro/nano-cavity lasers. Moreover, the introduction of gain and loss provides a fascinating playground to explore novel topological phases, which are in close relevance to non-Hermitian and paritytime symmetric quantum physics and are in general difficult to access using fermionic condensed matter systems. Here, we review the cutting-edge research on active topological photonics, in which optical gain plays a pivotal role. We discuss recent realizations of topological lasers of various kinds, together with the underlying physics explaining the emergence of topological edge modes. In such demonstrations, the optical modes of the topological lasers are determined by the dielectric structures and support lasing oscillation with the help of optical gain. We also address recent researches on topological photonic systems in which gain and loss themselves essentially influence on topological properties of the bulk systems. We believe that active topological photonics provides powerful means to advance micro/nanophotonics systems for diverse applications and topological physics itself as well.

show abstract

Topological insulator laser: Experiments

Cited by 1,180 publications

References 35 publications

Perspective on topological states of non-Hermitian lattices

Perspective on topological states of non-Hermitian lattices

Wannier-type photonic higher-order topological corner states induced solely by gain and loss

Active topological photonics

Contact Info

Product

Resources

About