1,720,963 research outputs found
Data for: Optical orientation, polarization pinning, and depolarization dynamics in optically confined polariton condensates
No full textExperimental data and numerical simulation results used to create the figures in the paper Gnusov, I., Sigurdsson, H., Baryshev, S., Ermatov, T., Askitopoulos, A. & Lagoudakis, P.G. (2020). Optical orientation, polarization pinning, and depolarization dynamics in optically confined polariton condensates. Physical Review B.</span
All-optical linear-polarization engineering in single and coupled exciton-polariton condensates
No full textWe demonstrate all-optical linear polarization control in semiconductor microcavities using an exciton-polariton condensate in an elliptically shaped optical trap. The microcavity inherent TE-TM splitting lifts the pseudospin degeneracy of the anisotropic trap ground state. The emerging fine structure modes are shown to be polarized linearly parallel and perpendicular to the trap major axis. We demonstrate polariton condensation into the excited pseudospin mode with high degree of linear polarization which rotates as we rotate the trap. We then extend our study to a system of two coupled linearly polarized condensates and demonstrate rich spin dynamics reflecting spontaneous synchronization and high correlation between the condensate pseudospins as a function of pump parameters. Our findings show a new type of polarization control with exciting perspectives in both spinoptronics and studies on extended systems of interacting nonlinear optical elements with anisotropic coupling strength and adjustable fine structure
Directional planar antennae in polariton condensates
No full textWe report on the realization of all-optical planar microlensing for exciton–polariton condensates in semiconductor microcavities. We utilize spatial light modulators to structure a nonresonant pumping beam into a plano–concave lens-shape focused onto the microcavity plane. When pumped above condensation threshold, the system effectively becomes a directional polariton antenna, generating an intense focused beam of coherent polaritons away from the pump region. The effects of pump intensity, which regulates the interplay between gain and blueshift of polaritons, as well as the geometry of the lens-shaped pump are studied, and a strategy to optimize the focusing of the condensate is proposed. Our work underpins the feasibility to guide nonlinear light in microcavities using nonresonant excitation schemes, offering perspectives on optically reprogramable on-chip polariton circuitry
Engineering Photon Statistics in a Spinor Polariton Condensate
No full textWe implement full polarization tomography on photon correlations in a spinor exciton-polariton condensate. Our measurements reveal condensate pseudospin mean-field dynamics spanning from stochastic switching between linear polarization components, limit cycles, and stable fixed points, and their intrinsic relation to the condensate photon statistics. We optically harness the cavity birefringence, polariton interactions, and the optical orientation of an incoherent exciton reservoir to engineer photon statistics with precise control. Our results demonstrate a smooth transition from a highly coherent to a super-thermal state of the condensate polarization components
Exciton radiative lifetime in a monoatomic carbon chain
No full textLinear carbon-based materials such as polyyne and cumulene oligomers provide a versatile platform for nano-physics and engineering. Direct gap quasi-1D polyyne structures are promising for the observation of strong and unusual excitonic effects arising due to the two-dimensional quantum confinement. Recently, we reported on the observation of sharp exciton peaks in low temperature photoluminescence spectra of polyyne chains (Kutrovskaya S et al 2020 Nano Lett.20 6502–9). Here, we analyze the time-resolved optical response of this system. We extend the non-local dielectric response theory to predict the exciton radiative lifetime dependence on the band-gap value and on the length of the chain. A good agreement between the experiment and the theory is achieved
Data for Engineering photon statistics in a spinor polariton condensate
No full textExperimental data and numerical simulation results used to create the figures in the paper Baryshev, S., Zasedatelev, A., Sigurdsson, H., Gnusov, I., Töpfer, J.D., Askitopoulos, A., & Lagoudakis, P.G. (2022) Engineering photon statistics in a spinor polariton condensate. Physical Review Letters.</span
Optical orientation, polarization pinning and depolarization dynamics in optically confined polariton condensates
No full textWe investigate the optical orientation, polarization pinning, and depolarization of optically confined semiconductor exciton-polariton condensates. We perform a complete mapping of the condensate polarization as a function of incident nonresonant excitation polarization and power. We utilize a ring-shaped excitation pattern to generate an exciton-induced potential that spatially confines polariton condensates into a single mode. We observe that formation of circular polarization in the condensate persists even for a weakly cocircularly polarized pump. By varying the excitation ring diameter we realize a transition from the condensate polarization being pinned along the coordinate-dependent cavity-strain axes, to a regime of zero degree of condensate polarization. Analysis through the driven-dissipative stochastic Gross-Pitaevskii equation reveals that this depolarization stems from a competition between sample induced in-plane polarization splitting and the condensate-reservoir overlap. An increase in the role of the latter results in weakening of the condensate fixed-point phase space attractors, and enhanced random phase space walk and appearance of limit cycle trajectories, reducing the degree of time-integrated polarization
Data for All-optical linear polarization engineering in single and coupled exciton-polariton condensates
No full textExperimental data and simulation results used to create the figures in the paper: Gnusov, I., Sigurdsson, H., Töpfer, J.D., Baryshev, S., Alyatkin, A., & Lagoudakis, P. G. (2021) All-optical linear polarization engineering in single and coupled exciton-polariton condensates. Physical Review Applied.</span
Exciton energy spectra in polyyne chains
No full textRecently, we have experimentally observed signatures of sharp exciton peaks in the photoluminescence spectra of bundles of monoatomic carbon chains stabilized by gold nanoparticles and deposited on a glass substrate. Here we estimate the characteristic energies of excitonic transitions in this complex quasi-one-dimensional nanosystem with use of the variational method. We show that the characteristic energy scale for the experimentally observed excitonic fine structure is governed by the interplay between the hopping energy in a Van der Waals quasicrystal formed by parallel carbon chains, neutral-charged exciton splitting, and positive-negative trion splitting. These three characteristic energies are an order of magnitude lower than the direct exciton binding energy
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