1,720,976 research outputs found
Coherent networks of polariton condensates in microcavities
No full textThe study of interacting many-element systems is as vital for our understanding of complex organisms, as it is important for the modelling of disease spreading in pandemics, and is a key element in the search for materials with novel properties. The presence of nonlinearities and interaction time-lags critically influences the dynamics and complicates control over these systems. Moreover, complexity in network structures rapidly scales with a larger number of elements and increasing degrees of freedom, often making them computationally intractable. Artificially engineered networks, on the other hand, can be used for the simulation and study of interacting systems, and pave the way for novel and unconventional computing paradigms. The implementation of these schemes is being explored in various fields such as electronics, photonics and quantum systems. In particular, lattices of polariton condensates in optical microcavities present a promising platform for the realisation of coupled network structures. Microcavity polaritons are light-weight bosonic quasi-particles formed by the strong coupling of cavity photons and quantum well excitons. Their hybrid light-matter character facilitates macroscopically accessible quantum degenerate states (condensates) at elevated temperatures. Large optical malleability, picosecond-timescale dynamics, and strong intrinsic nonlinearities highlight the potential of polariton lattices for future technological applications. The work presented in this PhD thesis investigates the interactions of coupled polariton condensates, and shows substantial advancements in both, the engineering and the manipulation of optically generated condensate lattices. In particular, the introduction of a laser feedback scheme for condensate density stabilisation makes it possible to accurately build macroscopic lattices of tuneable size and network architecture. The nonlinear dynamics and synchronisation phenomena of coupled condensates are explored in various coupling topologies, ranging from simply-connected structures to one- and two-dimensional periodic systems. Shaping of the polariton potential landscape by using spatially patterned lasers opens up an all-optical method of controlling couplings, interaction time-lags, and coherence properties in condensate lattices. The results and methods presented support the realisation of an ultra-fast delay-coupled nonlinear oscillator network, with precise control over individual couplings
Dataset for Thesis: An investigation into topological defects in polarities condensates
No full textExperimental data and numerical simulation results used to create the remaining figures in the University of Southampton Doctoral Thesis - An investigation into topological defects in polarities condensates.</span
Reservoir optics with exciton-polariton condensates
No full textWe investigate an all-optical microscale planar lensing technique based on coherent fluids of semiconductor cavity exciton-polariton condensates. Our theoretical analysis underpins the potential in using state-of-the-art spatial light modulation of nonresonant excitation beams to guide and focus polariton condensates away from their pumping region. The nonresonant excitation profile generates an excitonic reservoir that blueshifts the polariton mode and provides gain, which can be spatially tailored into lens shapes at the microscale to refract condensate waves. We propose several different avenues in controlling the condensate fluid, and demonstrate formation of highly enhanced and localised condensates away from the pumped reservoirs. This opens new perspectives in guiding quantum fluids of light and generating polariton condensates that are shielded from detrimental reservoir dephasing effects
Lotka-Volterra population dynamics in coherent and tunable oscillators of trapped polariton condensates
No full textWe demonstrate a regime in which matter-wave condensates of exciton-polaritons trapped in an elliptically shaped two-dimensional potential appear as a coherent mixture of ground and first-excited state of the quantum harmonic oscillator. This system resembles an optically controllable two-level system and produces near terahertz harmonic oscillations of the condensate’s center of mass along the major axis of the elliptical trapping potential. The population ratio between the two trap levels is tunable through the excitation laser power and is shown to follow Lotka-Volterra dynamics. Furthermore, we demonstrate coherence formation between two spatially displaced trapped condensate oscillators - the polaritonic analogue of Huygen’s clock synchronization for coupled condensate oscillators
Data for Lotka-Volterra population dynamics in coherent and tunable oscillators of trapped polariton condensates
No full textExperimental data and numerical simulation results used to create the figures in the paper Töpfer, J.D., Sigurdsson, H., Alyatkin, S. & Lagoudakis, P. (2020). Lotka-Volterra population dynamics in coherent and tunable oscillators of trapped polariton condensates. Physical Review B.</span
Data for: Polariton spin jets through optical control
No full textExperimental data and simulation results used to create the figures in the paper: Pickup, L., Töpfer, J.D., Sigurdsson, H. & Lagoudakis, P. G. (2021) Polariton spin jets through optical control. Physical Review B.</span
Dataset for: Reservoir optics with exciton-polariton condensates
No full textDataset for paper entitled "Reservoir optics with exciton-polariton condensates" in Physical Review B.</span
Data for Time-Delay Polaritonics
No full textExperimental data and numerical simulation results used to create the figures in the paper Töpfer, J.D., Sigurdsson, H., Pickup, L. & Lagoudakis, P. (2019). Time-Delay Polaritonics. Communications Physics.</span
Dataset supporting an article 'Quantum Vortex Formation in the "Rotating Bucket" Experiment with Polariton Condensates'
No full text Data set for Science Advances research article with title:
Quantum Vortex Formation in the "Rotating Bucket" Experiment with Polariton Condensates
This dataset contains the data for figures 2, 3, 4, S1, S2, and S3 along with details on the scale and how to plot the data, contained in the README.txt file.
The README.txt file gives a detailed description of each text file and the associated journal article. </span
Engineering spatial coherence in lattices of polariton condensates
No full textArtificial lattices of coherently coupled macroscopic states are at the heart of applications ranging from solving hard combinatorial optimization problems to simulating complex many-body physical systems. The size and complexity of the problems scale with the extent of coherence across the lattice. Although the fundamental limit of spatial coherence depends on the nature of the couplings and lattice parameters, it is usually engineering constraints that define the size of the system. Here, we engineer polariton condensate lattices with active control on the spatial arrangement and condensate density that results in near-diffraction limited emission, and spatial coherence that exceeds by nearly two orders of magnitude the size of each individual condensate. We use these advancements to unravel the dependence of spatial correlations between polariton condensates on the lattice geometry.</p
- …
