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Nonlinear bifurcation diagrams of the current states of microcavity exciton-polaritons in the lattice
摘要： We study nonequilibrium properties of exciton-polaritons in an incoherently driven semiconductor microcavity with an embedded weak-contrast periodic lattice. Within the framework of mean-field theory, we describe nonlinear eigenstates of coherent exciton polaritons having the structure of Bloch waves and identify nonlinear current states at the boundaries of Brillouin zone. We demonstrate a profound modification of the eigenfrequency-momenta bifurcation diagrams of the condensate evoked by exciton-exciton interactions. The discussed phenomenon occurs for the states possessing high degree of symmetry, i.e. in particular, for the states lying at the centre or at the boundary of Brillouin zone.
关键词： exciton-polaritons,semiconductor microcavity,Bloch waves,nonlinear bifurcation,Brillouin zone
更新于2025-09-23 15:21:21
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Light-induced transition between the strong and weak coupling regimes in planar waveguide with GaAs/AlGaAs quantum well
摘要： Exciton-polaritons in planar waveguides are of great interest for application in polariton circuits due to the large polariton group velocity in the plane of the waveguide. We demonstrate the ability to control the exciton-polariton coupling by light in an AlGaAs-based planar waveguide with GaAs/AlGaAs quantum well. The transition between strong and weak coupling regimes observed with increasing light intensity is explained by the increase in exciton mode losses due to the quantum well charging. This assumption is confirmed by the reflection spectroscopy with resonant illumination.
关键词： AlGaAs,GaAs,planar waveguides,strong coupling,quantum well,exciton-polaritons,weak coupling
更新于2025-09-23 15:21:01
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: From quantum dots to bulk crystals and additional boundary conditions for Rydberg exciton-polaritons
摘要： We propose schemes for calculation of optical functions of a semiconductor with Rydberg excitons for a wide interval of dimensions. We have started with a zero-dimensional structure (quantum dot), then going to one-dimensional (quantum wire), two-dimensional (quantum wells and wide quantum wells), and ?nally three-dimensional bulk crystals; our analytical ?ndings are illustrated numerically, showing an agreement with available experimental data. Calculations including exciton-polaritons are performed; the case of a large number of polariton branches is discussed, and obtained theoretical absorption spectra show good agreement with experimental data.
关键词： quantum wells,bulk crystals,exciton-polaritons,quantum wires,Rydberg excitons,quantum dots
更新于2025-09-23 15:21:01
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Polariton condensation in photonic crystals with high molecular orientation
摘要： We study Frenkel exciton-polariton Bose–Einstein condensation in a two-dimensional defect-free triangular photonic crystal with an organic semiconductor active medium containing bound excitons with dipole moments oriented perpendicular to the layers. We ?nd photonic Bloch modes of the structure and consider their strong coupling regime with the excitonic component. Using the Gross– Pitaevskii equation for exciton polaritons and the Boltzmann equation for the external exciton reservoir, we demonstrate the formation of condensate at the points in reciprocal space where photon group velocity equals zero. Further, we demonstrate condensation at non-zero momentum states for transverse magnetic-polarized photons in the case of a system with incoherent pumping, and show that the condensation threshold varies for different points in the reciprocal space, controlled by detuning.
关键词： organic semiconductors,photonic crystalls,photonics,exciton polaritons,Bose–Einstein condensate
更新于2025-09-23 15:21:01
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Self-hybridized exciton-polaritons in multilayers of transition metal dichalcogenides for efficient light absorption
摘要： Transition metal dichalcogenides (TMDCs) have attracted significant attention recently in the context of strong light-matter interaction. To observe strong coupling using these materials, excitons are typically hybridized with resonant photonic modes of stand-alone optical cavities, such as Fabry-Pérot microcavities or plasmonic nanoantennas. Here, we show that thick flakes of layered van der Waals TMDCs can themselves serve as low quality resonators due to their high background permittivity. Optical modes of such “cavities” can in turn hybridize with excitons in the same material. We perform an experimental and theoretical study of such self-hybridization in thick flakes of four common TMDC materials: WS2, WSe2, MoS2, and MoSe2. We observe splitting in reflection and transmission spectra in all four cases and provide angle-resolved dispersion measurements of exciton-polaritons as well as thickness-dependent data. Moreover, we observe significant enhancement and broadening of absorption in thick TMDC multilayers, which can be interpreted in terms of strong light-matter coupling. Remarkably, absorption reaches >50% efficiency across the entire visible spectrum, while simultaneously being weakly dependent on polarization and angle-of-incidence. Our results thus suggest formation of self-hybridized exciton-polaritons in thick TMDC flakes, which in turn may pave the way towards polaritonic and optoelectronic devices in these simple systems.
关键词： transition metal dichalcogenides,exciton-polaritons,strong coupling,nanocavities
更新于2025-09-23 15:21:01
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Monitoring strong coupling in nonlocal plasmonics with electron spectroscopies
摘要： Plasmon-exciton polaritons provide exciting possibilities to control light-matter interactions at the nanoscale by enabling closer investigation of quantum optical effects and facilitating novel technologies based, for instance, on Bose-Einstein condensation and polaritonic lasing. Nevertheless, observing and visualizing polaritons is challenging, and traditional optical microscopy techniques often lead to ambiguities regarding the emergence and strength of the plasmon-exciton coupling. Electron microscopy offers a more robust means to study and verify the nature of plexcitons, but it is still hindered by instrument limitations and resolution. A simple theoretical description of electron beam-excited plexcitons is therefore vital to complement ongoing experimental efforts. Here we apply analytic solutions for the electron-loss and photon-emission probabilities to evaluate plasmon-exciton coupling studied either with the recently adopted technique of electron energy-loss spectroscopy, or with the so-far unexplored in this context cathodoluminescence spectroscopy. Foreseeing the necessity to account for quantum corrections in the plasmonic response, we extend these solutions within the framework of general nonlocal hydrodynamic descriptions. As a specific example, we study core-shell spherical plasmon-molecule hybrids, going beyond the standard local-response approximation through the hydrodynamic Drude model for screening and the generalized nonlocal optical response theory for nonlocal damping. We show that electron microscopies are extremely powerful in describing the interaction of emitters with the otherwise weakly excited by optical means higher-order plasmonic multipoles, a response that survives when quantum-informed models are considered. Our work provides, therefore, both a robust theoretical background and supporting argumentation to the open quest for improving and further utilizing electron microscopies in strong-coupling nanophotonics.
关键词： electron energy-loss spectroscopy,nonlocal hydrodynamic descriptions,cathodoluminescence spectroscopy,quantum plasmonics,Plasmon-exciton polaritons
更新于2025-09-23 15:19:57
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A cost-effective realization of multimode exciton-polaritons in single-crystalline microplates of a layered metal-organic framework
摘要： We report the observation of multimode exciton-polaritons in single-crystalline microplates of a two-dimensional (2D) layered Metal-Organic Framework (MOF), which can be synthesized through a facile solvothermal approach, thereby eliminating all fabrication complexities usually involved in the construction of polariton cavities. With a combination of experiments and theoretical modelling, we have found that the exciton-polaritons are formed at room temperature, as a result of a strong coupling between Fabry-Perot cavity modes formed inherently by two parallel surfaces of a microplate and Frenkel excitons provided by the 2D layers of dye molecular linkers in the MOF. Flexibility in rational selection of dye linkers for synthesizing such MOFs renders a large-scale, low-cost production of solid-state, micro- exciton-polaritonic devices operating in the visible and near infrared (NIR) range. Our work introduces the MOF as a new class of potential materials to explore polariton-related quantum phenomena in a cost-effective manner.
关键词： Strong Coupling,Exciton-Polaritons,Multimode Coupling,Metal-Organic Framework,Angle-Resolved Reflectivity,Rhodamine B
更新于2025-09-19 17:15:36
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Nonlinear polaritons in a monolayer semiconductor coupled to optical bound states in the continuum
摘要： Optical bound states in the continuum (BICs) provide a way to engineer very narrow resonances in photonic crystals. The extended interaction time in these systems is particularly promising for the enhancement of nonlinear optical processes and the development of the next generation of active optical devices. However, the achievable interaction strength is limited by the purely photonic character of optical BICs. Here, we mix the optical BIC in a photonic crystal slab with excitons in the atomically thin semiconductor MoSe2 to form nonlinear exciton-polaritons with a Rabi splitting of 27 meV, exhibiting large interaction-induced spectral blueshifts. The asymptotic BIC-like suppression of polariton radiation into the far field toward the BIC wavevector, in combination with effective reduction of the excitonic disorder through motional narrowing, results in small polariton linewidths below 3 meV. Together with a strongly wavevector-dependent Q-factor, this provides for the enhancement and control of polariton–polariton interactions and the resulting nonlinear optical effects, paving the way toward tuneable BIC-based polaritonic devices for sensing, lasing, and nonlinear optics.
关键词： nonlinear exciton-polaritons,MoSe2,Rabi splitting,photonic crystal slab,Optical bound states in the continuum
更新于2025-09-19 17:13:59
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Transition Between Exciton-Polariton and Coherent Photonic Lasing in All-Inorganic Perovskite Microcuboid
摘要： All-inorganic lead halide perovskites are ideal platforms to investigate the fundamental physics of the light-matter interactions, due to their strong oscillator strength at room temperature and various microstructures. In this paper, we investigated strong exciton-photon coupling and coherent photonic lasing in a same high-quality self-assembled CsPbBr3 perovskite microcuboid grown by a chemical vapor deposition method. The vacuum Rabi splitting of polariton up to 309 meV, and the exciton-like and photon-like components in low polariton states at different cavity-exciton detuning, were revealed by angle-resolved photoluminescence spectra at room temperature. Moreover, we realized a coherent photonic lasing with a high quality-factor (4153) and narrow linewidth (0.13 nm) in the microcuboid above threshold (16 μJ/cm2), originated from population inversion. Significantly, the interference pattern of the coherent lasing through the Young's double-slit interference method based on far-field Fourier optical system, directly indicate the parity (odd) of the lasing mode and the asymmetric electric-field distribution in the CsPbBr3 microstructure. Our work demonstrates for the first time a transition from the strong coupling regime (vertical Fabry–Pérot oscillation) to weak coupling regime (lateral Fabry–Pérot oscillation) in such self-assembled microcuboid under the competition between gain and internal loss. Based on this mechanism, a considerable promise is expected to enrich the functions of micro-nano structure photoelectric devices by precisely controlling the quality-factor and gain of such microstructure.
关键词： Exciton-polaritons,Young's interference,Perovskite microcuboid,Photonic lasing,Fabry–Pérot microcavity
更新于2025-09-16 10:30:52
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Nonlinear optics at excited states of exciton polaritons in two-dimensional atomic crystals
摘要： Exciton polaritons (EP) are partial-light partial-matter quasiparticles in semiconductors demonstrating striking quantum phenomena such as Bose-Einstein condensation and single-photon nonlinearity. In these phenomena, the governing process is the EP relaxation into the ground states upon excitation, where various mechanisms are extensively investigated with thermodynamic limits. However, the relaxation process becomes drastically different and could significantly advance the understanding of EP dynamics for these quantum phenomena, when excited states of EP are involved. Here, for the first time, we observe nonlinear optical responses at the EP excited states in a monolayer tungsten disulphide (WS2) microcavity, including dark excited states and dynamically metastable upper polariton band. The nonlinear optics leads to unique emissions of ground states with prominent valley degree of freedom (DOF) via anomalous relaxation process, which is applicable to a wide range of semiconductors from monolayer transition metal dichalcogenides (TMDs) to emerging halide perovskites. This work promises possible approaches to challenging experiments such as valley polariton condensation. Moreover, it also constructs a valley-dependent solid state three-level system for terahertz photonics and stimulated Raman adiabatic passage.
关键词： excited states,exciton-polaritons,relaxation dynamics,Nonlinear optics,monolayer transition metal dichalcogenide
更新于2025-09-16 10:30:52