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The layer-by-layer buildup of a two-dimensional transition metal dichalcogenide monolayer to form a stack is an important development for these materials, which performs many remarkable properties in the light–matter interaction. Herein, we find clear evidence of exciton–polaritons emerging from WS2/hBN/WS2 heterostructures embedded in a dielectric microcavity under optical pumping. A large Rabi splitting of 15 meV is observed at room temperature, which increases to 25 meV at 5 K. An all-dielectric Fabry–Pérot microcavity provides a simple but effective way to study the room temperature strong coupling between cavity photons and excitons. Our results pave the way for room-temperature polaritonic devices based on quantum-well van der Waals heterostructures. [ABSTRACT FROM AUTHOR]

All-inorganic cesium lead halide perovskite quantum dots have recently received much attention as promising optoelectronic materials with great luminescent properties and bright application prospect in lighting, lasing, and photodetection. Although notable progress has been achieved in lighting applications based on such media, the performance could still be improved. Here, we demonstrate that the light emission from the perovskite QDs that possess high intrinsic luminous efficiency can be greatly enhanced by using metallic thin films, a technique that was usually considered only useful for improving the emission of materials with low intrinsic quantum efficiency. Eleven-fold maximal PL enhancement is observed with respect to the emission of perovskite QDs on the bare dielectric substrate. We explore this remarkable enhancement of the light emission originating from the joint effects of enhancing the incident photonic absorption of QDs at the excitation wavelength by means of the zero-order optical asymmetric Fabry–Perot-like thin film interference and increasing the radiative rate and quantum efficiency at the emission wavelength mediated by surface plasmon polaritons. We believe that our approach is also potentially valuable for the enhancement of light emission of other fluorescent media with high intrinsic quantum efficiency. [ABSTRACT FROM AUTHOR]

Cavity polaritons, originating from the strong coupling effect between cavity modes and excitons, have been tremendously investigated because of their high potential in new or quantum optoelectronic devices. Among them, realization of their dynamic controllability is highly desirable for real applications. In this work, we present a dynamic modulation of cavity polaritons via strain-engineering in the ZnO whispering gallery microcavity. By using a home-made strain apparatus, a nearly uniaxial stress is precisely applied to ZnO microwires, thus inducing an internal strain along its c-axis. Dynamic tuning of cavity polariton modes is clearly characterized by angle-resolved microphotoluminescence spectroscopy. The coupled oscillator's model with fitting parameters of strain-dependent excitons' energies can well describe the modes' redshift. Moreover, we show that the modes' redshift can also be understood by the strain-induced refractive index increase, described by the Lorentz model, of which the underlying mechanism is also related to light-exciton strong coupling. Finally, the strain-engineered dynamic tuning of polariton lasing modes is demonstrated as well, and this actually provides convincing evidence for the polariton states surviving above the threshold. This work indicates that strain-engineered cavity polaritons would pave an alternative way for developing polariton-based integrated or flexible optoelectronic devices. [ABSTRACT FROM AUTHOR]

The band-edge emission lifetime in a single ZnO tetrapod is studied by using the time-resolved confocal micro-photoluminescence (TR- μ PL) spectroscopic technique at room temperature. By performing μ PL and TR- μ PL mapping along the tapered arm of tetrapod, we observe whispering gallery mode (WGM) polaritons and find that the predominant radiative lifetime of exciton polaritons decreases linearly with increasing the surface-to-volume ratio of the sample. This behavior is ascribed to the surface electric field induced enhancement of the radiative decay rate of the exciton-like polaritons coupling with LO phonons. [ABSTRACT FROM AUTHOR]

A hybrid plasmonic–photonic crystal consisting of a low-cost metal (Al or Cu) covered by self-assembly polystyrene sub-micro sphere arrays is fabricated. The angle-resolved reflection spectra show the existence of propagating optical surface modes in the structure. Especially, under normal incidence, five surface modes can be observed clearly. With the help of theoretical calculation, the origin of surface resonance modes is confirmed. From both the experiment and simulation, the surface plasmon modes supported by this structure possess high Q factors, which are comparable with those of the modes based on noble metals. Moreover, with a dielectric layer deposited on the top of the structure, its potential application for surface plasma polariton sensors is proposed. [ABSTRACT FROM AUTHOR]

A robust exciton-polariton effect in a ZnO whispering gallery microcavity well above room temperature is presented. The lower polariton branches are tuned by current induced thermal effect. The red shift can be as large as ∼40 meV. It is found that the strong coupling can be preserved and the polariton-phonon interaction quenching effect remains up to ∼550 K, while the Rabi splitting is about 330 meV. The tuning speed is in the order of millisecond, showing its potential in polariton-based optoelectronic device application. [ABSTRACT FROM AUTHOR]

We demonstrate a novel way to realize room-temperature polariton parametric scattering in a one-dimensional ZnO microcavity. The polariton parametric scattering is driven by a polariton condensate, with a balanced polariton pair generated at the adjacent polariton mode. This parametric scattering is experimentally investigated by the angle-resolved photoluminescence spectroscopy technique under different pump powers and it is well described by the rate equation of interacting bosons. The direct relation between the intensity of the scattered polariton signal and that of the polariton reservoir is acquired under nonresonant excitation, exhibiting the explicit nonlinear characteristic of this room-temperature polariton parametric process. [ABSTRACT FROM AUTHOR]