Strong light-matter interaction enriches topological photonics by dressing light with matter, which provides the possibility to realize tuneable topological devices with immunity to defects. Topological exciton polaritons, half-light half-matter quasiparticles with giant optical nonlinearity represent a unique platform for active topological photonics with phase tunability. Previous demonstrations of exciton polariton topological insulators still demand cryogenic temperatures and their topological properties are usually fixed without phase tunability. Here, we experimentally demonstrate a room-temperature exciton polariton topological insulator with active phase tunability in a perovskite zigzag lattice. Polarization serves as a degree of freedom to control the reversible transition between distinct topological phases, thanks to the polarization-dependent anisotropy in halide perovskite microcavities. The topologically nontrivial polariton states localized in the edges persist in the presence of a natural defect, showing strong immunity to disorder. We further demonstrate that exciton polaritons can condense into the topological edge states under optical pumping. These results provide an ideal platform for realizing tuneable topological polaritonic devices with room-temperature operation, which can find important applications in optical control, modulation and switching.
Hybrid halide perovskites are now considered as low-cost materials for contemporary research in photovoltaics and nanophotonics. In particular, because these materials can be solution processed, they represent a great hope for obtaining low-cost devices. While the potential of 2D layered hybrid perovskites for polaritonic devices operating at room temperature has been demonstrated in the past, the potential of the 3D perovskites has been much less explored for this particular application. Here, we report the strong exciton-photon coupling with 3D bromide hybrid perovskite. Cavity polaritons ar…
Two dimensional (2D) perovskites are promising materials for photonic applications, given their outstanding nonlinear optical properties, ease of fabrication and versatility. In particular, exploiting their high oscillator strength, the crystalline form of 2D perovskites can be used as excitonic medium in optical microcavities, allowing for the study of their optical properties in the strong light-matter coupling regime. While polariton condensation has been observed in different materials at room temperature, here we observe for the first time two distinct threshold processes in a 2D perovski…
Optically reconfigurable canalization of exciton-polaritons in a non-hyperbolic perovskite
Nanyang Technological University（南洋理工大学）；B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine（乌克兰国家科学院B.维尔金低温物理与工程研究所）；Institut Universitaire de France (IUF)（法兰西学院）；National University of Singapore（新加坡国立大学）
Bose-Einstein condensation in strongly correlated lattices provides the possibility to coherently generate macroscopic quantum states, which have attracted tremendous attention as ideal platforms for quantum simulation. Ultracold atoms in optical lattices are one of such promising systems, where their realizations of different phases of matter exhibit promising applications in condensed matter physics, chemistry, and cosmology. Nevertheless, this is only accessible with ultralow temperatures in the nano to micro Kelvin scale set by the typical inverse mass of an atom. Alternative systems such …
Exciton-polaritons in semiconductor microcavities generate fascinating effects such as long-range spatial coherence and Bose-Einstein Condensation (BEC), which are attractive for their potential use in low threshold lasers, vortices and slowing light, etc. However, currently most of exciton-polariton effects either occur at cryogenic temperature or rely on expensive cavity fabrication procedures. Further exploring new semiconductor microcavities with stronger exciton photon interaction strength is extensively needed. Herein, we demonstrate room temperature photon exciton strong coupling in hyb…
Exciton-polaritons, elementary excitations arising from the strong coupling regime between photons and excitons in insulators or semiconductors, represent a promising platform for studying quantum fluids of light and realizing prospective all-optical devices. Among different materials for room temperature polaritonic devices, two-dimensional (2D) layered perovskites have recently emerged as one of the promising candidates thanks to their prominent excitonic features at room temperature. Here we report on the experimental demonstration of exciton-polaritons at room temperature in resonant metas…
Polaritonic devices exploit the coherent coupling between excitonic and photonic degrees of freedom to perform highly nonlinear operations with low input powers. Most of the current results exploit excitons in epitaxially grown quantum wells and require low temperature operation, while viable alternatives have yet to be found at room temperature. Here we show that large single-crystal flakes of two-dimensional layered perovskite are able to sustain strong polariton nonlinearities at room temperature with no need to be embedded in an optical cavity. In particular, exciton-exciton interaction en…
Reconfigurable ultrafast perovskite polariton logic gates via nonlinear dynamics
Peking University（北京大学）；National Center for Nanoscience and Technology（国家纳米科学中心）；University of Chinese Academy of Sciences（中国科学院大学）；Xi'an Jiaotong University（西安交通大学）；Nanyang Technological University（南洋理工大学）；Paderborn University（帕德博恩大学）
Room-temperature cavity exciton-polariton condensation in perovskite quantum dots
IBM Research Europe – Zurich（IBM欧洲苏黎世研究中心）；ETH Zurich（苏黎世联邦理工学院）；Institute of Materials Science of Sevilla, Consejo Superior de Investigaciones Científicas − Universidad de Sevilla (CSIC-US)（塞维利亚材料科学研究所，西班牙国家研究委员会-塞维利亚大学）；Laboratory of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich（苏黎世联邦理工学院化学与应用生物科学学院无机化学实验室）；Empa − Swiss Federal Laboratories for Materials Science and Technology（瑞士联邦材料科学与技术研究院）
Room-temperature polariton condensate in a two-dimensional hybrid perovskite
Carl von Ossietzky Universität Oldenburg（奥格斯堡卡尔冯奥西茨基大学）；University of Valencia（瓦伦西亚大学）；University of Exeter（埃克塞特大学）；Fraunhofer-Institute for Applied Optics and Precision Engineering IOF（弗劳恩霍夫应用光学和精密工程研究所IOF）；Friedrich Schiller University（弗里德里希·席勒大学）；Bar-Ilan Univ.（巴伊兰大学）；Weizmann Institute of Science（魏茨曼科学研究所）
Exciton-polaritons are mixed light-matter excitations that result from the strong coupling regime between an active excitonic material and photonic resonances. Harnessing these hybrid excitations provides a rich playground to explore fascinating fundamental features, such as out-of-equilibrium Bose-Einstein condensation and quantum fluids of light, as well as novel mechanisms to be exploited in optoelectronic devices. Here, we investigate experimentally the formation of exciton-polaritons arising from the mixing between hybrid inorganic-organic perovskite excitons and an optical Bound state In…
Light-matter coupling in excitonic materials has been the subject of intense investigation due to emergence of new excitonic materials. Two-dimensional layered hybrid organic/inorganic perovskites (2D HOIPs) support strongly bound excitons at room-temperatures with some of the highest oscillator strengths and electric loss tangents among the known excitonic materials. Here, we report strong light-matter coupling in Ruddlesden-Popper phase 2D-HOIPs crystals without the necessity of an external cavity. We report concurrent occurrence of multiple-orders of hybrid light-matter states via both refl…
Topological physics and in particular its connection with artificial gauge fields is a forefront topic in different physical systems, ranging from cold atoms to photonics and more recently semiconductor dressed exciton-photon states, called polaritons. Engineering the energy dispersion of polaritons in microcavities through nanofabrication or exploiting the intrinsic material and cavity anisotropies has demonstrated many intriguing effects related to topology and emergent gauge fields. Here, we show that we can control the Berry curvature distribution of polariton bands in a strongly coupled o…
Achieving electrical injection of exciton-polaritons, half-light, half-matter quasiparticles arising from the strong coupling between photonic and excitonic resonances, is a crucial milestone to scale up polaritonic devices such as optical computers, quantum simulators and inversionless lasers. Here we present a new approach to achieve strong coupling between electrically injected excitons and photonic bound states in the continuum of a dielectric metasurface monolithically patterned in the channel of a light-emitting transistor. Exciton-polaritons are generated by coupling electrically inject…
Excitons, bound electron-hole pairs, in Two-Dimensional Hybrid Organic Inorganic Perovskites (2D HOIPs) are capable of forming hybrid light-matter states known as exciton-polaritons (E-Ps) when the excitonic medium is confined in an optical cavity. In the case of 2D HOIPs, they can self-hybridize into E-Ps at specific thicknesses of the HOIP crystals that form a resonant optical cavity with the excitons. However, the fundamental properties of these self-hybridized E-Ps in 2D HOIPs, including their role in ultrafast energy and/or charge transfer at interfaces, remain unclear. Here, we demonstra…
Lead-halide perovskites are highly promising for various optoelectronic applications including laser devices. However, fundamental photophysics describing the lasing behaviour in this material family have not been investigated systematically, and thus the detailed lasing mechanism remains veiled. Here, we demonstrate that an all-inorganic perovskite shows a lasing emission based on a novel principle. A series of photoluminescence experiment results reveals that the excited state of CsPbBr3 single crystal exhibits free carrier nature. In a form of microcavity, on the other hand, the CsPbBr3 sin…
Microcavity polaritons are light-matter quasiparticles that arise from the strong coupling between excitons and photons confined in a semiconductor microcavity. They typically operate at visible or near visible wavelengths. They combine the properties of confined electromagnetic fields, including a sizeable spin-orbit coupling, and the sensitivity to external magnetic fields and particle interactions inherited from their partly matter nature. These features make polaritons an excellent platform to study topological phases in photonics in one and two dimensional lattices, which band properties …
Exciton-polaritons resulting from the strong exciton-photon interaction stimulate the development of novel coherent light sources with low threshold, long range spatial, and temporal coherence to circumvent the ever increasing energy demands of optical communications. Polaritons from bound states in the continuum (BICs) are promising for Bose-Einstein condensation owing to their infinite quality factors that enlarge photon lifetimes and benefit polariton accumulations. However, BIC polariton condensation remains limited to cryogenic temperatures ascribed to the small exciton binding energies o…
Topological concepts have been applied to a wide range of fields in order to successfully describe the emergence of robust edge modes that are unaffected by scattering or disorder. In photonics, indications of lasing from topologically protected modes with improved overall laser characteristics were observed. Here, we study exciton-polariton microcavity traps that are arranged in a one-dimensional Su-Schrieffer-Heeger lattice and form a topological defect mode from which we unequivocally observe highly coherent polariton lasing. Additionally, we confirm the excitonic contribution to the polari…
Layered topological insulators, for example, Bi$_2$Se$_3$ are optically hyperbolic materials in a range of THz frequencies. Such materials possess deeply subdiffractional, highly directional collective modes: hyperbolic phonon-polaritons. In thin crystals the dispersion of such modes is split into discrete subbands and is strongly influenced by electron surface states. If the surface states are doped, then hybrid collective modes result from coupling of the phonon-polaritons with surface plasmons. The strength of the hybridization can be controlled by an external gate that varies the chemical …
Twisted two-dimensional bi-layers offer exquisite control on the electronic bandstructure through the interlayer rotation and coupling, enabling magic-angle flat-band superconductivity and moiré excitons. Here, we demonstrate how analogous principles, combined with large anisotropy, enable extreme control and manipulation of the photonic dispersion of phonon polaritons (PhPs) in van der Waals (vdW) bi-layers. We experimentally observe tunable topological transitions from open (hyperbolic) to closed (elliptic) dispersion contours in twisted bi-layered α-MoO3 at photonic magic angles, induced by…
Systems with strong light-matter interaction opens up new avenues for studying topological phases of matter. Examples include exciton-polaritons, mixed light-matter quasiparticles, where the topology of the polaritonic band structure arises from the collective coupling between matter wave and optical fields strongly confined in periodic dielectric structures. Distinct from light-matter interaction in a uniform environment, the spatially varying nature of the optical fields leads to a fundamental modification of the well-known optical selection rules, which were derived under the plane wave app…
Optical field interacting with a topologically protected one-dimensional helical state is shown to support a one-dimensional plasmon-polariton that is characterized by a non-linear dispersion. In a two-dimensional Dirac magnet these electro-optical excitations are confined to domain walls, thus, offering a possibility to manipulate quantum optical states by altering magnetic domain configurations. An exact spectral equation for such a topological plasmon-polariton is derived.
Vorticity is a key ingredient to a broad variety of fluid phenomena, and its quantised version is considered to be the hallmark of superfluidity. Circulating flows that correspond to vortices of a large topological charge, termed giant vortices, are notoriously difficult to realise and even when externally imprinted, they are unstable, breaking into many vortices of a single charge. In spite of many theoretical proposals on the formation and stabilisation of giant vortices in ultra-cold atomic Bose-Einstein condensates and other superfluid systems, their experimental realisation remains elusiv…
