1,720,976 research outputs found
Dataset for 'A yellow polariton condensate in a dye filled microcavity'
No full textIncluded here are the raw datasets for the dispersion imaging and interferometry in the paper A yellow polariton condensate in a dye filled microcavity. / Cookson, Tamsin; Georgiou, Kyriacos; Zasedatelev, Anton; Grant, Richard T.; Virgili, Tersilla; Cavazzini, Marco; Galeotti, Francesco ; Clark, Casper; Berloff, Natalia G.; Lidzey, David G.; Lagoudakis, Pavlos G. In: Advanced Optical Materials, 05.05.2017.
The dataset is an updated version of the dataset DOI:10.5258/SOTON/D0093 and should be used in preference.</span
An Investigation into topological defects in polariton condensates
No full textPolaritons are quasiparticles arising from the state of strong coupling between a an exciton - another quasiparticle, made from an electron hole pair - with a photon trapped in a microcavity. The high binding energy of Frenkel excitons allows for polariton condensation to occur at room temperature, leading to the possibility for polaritons to be used in optoelectronic devices. The weaker-bound Wannier-Mott excitons in inorganic semiconductors require cryogenic temperatures to be excited, but, due to years of investigation, are being made into low-disorder cavities, allowing for the possible study of more exotic phenomena, such as vorticity, bistability, condensate coupling and lattices of condensates. Both regimes have their clear advantages and disadvantages, but ultimately, it is the study of both that will lead to a deeper understanding of the field. This thesis looks at the coherence in between coupled condensates in a polariton dyad, extracting the coherence length for the system. Then, the creation of vortices varying topological charge is demonstrated by injecting an odd number of polariton condensates at the vertices of a regular polygon and imposing frustration into the system by controlling the interactions across vertices. Stable spatially localised circular energy flows can be observed circulating around a central vortex. The creation of so-called giant vortices, formed at the centre of a polygon on a non-zero density background, present as platform for the study of vorticity in superfluids. Polariton condensation in the yellow part of the visible spectrum from a planar organic semiconductor microcavity containing the molecular dye BODIPY-Br is shown. The experimental fingerprints of polariton condensation under non-resonant optical excitation are presented , including the non-linear dependence of the emission intensity, linewidth narrowing and wavelength blueshift with increasing excitation density, obtained from single pulse dispersion imaging which allows us to visualise the collapse of the energy distribution upon reaching threshold. Finally, single shot interferometry is used to observe unpinned spontaneous vortices in organic polariton condensates.<br/
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
Operation of a continuous flow liquid helium magnetic microscopy cryostat as a closed cycle system
No full textWe demonstrate successful operation of a continuous flow liquid helium magnetic cryostat (Oxford Instruments, Microstat MO) in closed cycle operation using a modular cryocooling system (ColdEdge Technologies, Stinger). For the system operation, we have developed a custom gas handling manifold and we show that despite the lower cooling power of the cryocooler with respect to the nominal cryostat cooling power requirements, the magnetic cryostat can be operated in a stable manner. We provide the design of the gas handling manifold and a detailed analysis of the system performance in terms of cooling times, magnetic field ramping rates, and vibrations at the sample. Base temperatures can be reached within 10 h while the superconducting magnet can be energized at a ramping rate of 0.5 T/min. Vibrations are measured interferometrically and show amplitudes with a root mean square on the order of 5 nm, permitting the use of the system for sensitive magnetic microscopy experiments.<br/
Data to support the article "Spontaneous formation of time-periodic vortex cluster in nonlinear fluids of light"
No full textData from experimental measurements and numerical simulations used to create the figures and animations in the paper Sitnik, K., Alyatkin, S., Töpfer, J.D., Gnusov, I., Cookson, T., Sigurdsson, H., & Lagoudakis, P.G. (2022) Spontaneous formation of time-periodic vortex cluster in nonlinear fluids of light. in Physical Review Letters.</span
Data for Engineering spatial coherence in lattices of polariton condensates
No full textExperimental data and numerical simulation results used to create the figures in the paper J. D. Töpfer, I. Chatzopoulos, H. Sigurdsson, T. Cookson, Y. G. Rubo, and P. G. Lagoudakis (2020), Engineering spatial coherence in lattices of polariton condensates, Optica.</span
Occupancy-driven Zeeman suppression and inversion in trapped polariton condensates
Full text linkWe study the magneto-photoluminescence of an optically trapped exciton-polariton condensate in a planar semiconductor microcavity with multiple In0.08Ga0.92As quantum wells. Extremely high condensate coherence time and continuous control over the polariton confinement are among the advantages provided by optical trapping. This allows us to resolve magnetically induced μeV fine-energy shifts in the condensate and identify unusual dynamical regions in its parameter space. We observe polariton Zeeman splitting and, in small traps with tight confinement, demonstrate its full parametric screening when the condensate density exceeds a critical value, reminiscent of the spin-Meissner effect. For larger optical traps, we observe a complete inversion in the Zeeman splitting as a function of power, underlining the importance of condensate confinement and interactions with its background reservoir excitons
Sensing spatial coherence of light with metamaterial surfaces
No full textWe report on a discovery that homogeneous metallic non-diffracting metasurfaces of a certain type allow robust speckle-free discrimination between different degrees of the spatial coherence of light. The effect has no direct analogue in natural materials and has been previously unseen in metamaterials (and metasurfaces in particular). It results in a qualitative change of the optical response of metasurfaces, whereby their transmission (and reflection) spectra acquires different spectral components, depending on whether the nano-structures are illuminated with spatially coherent or incoherent light. This effect is robust and exceptionally strong (e.g., the resulting absolute change in transmission exceeds 50%), which makes it immediately suitable for practical applications, such as optical metrology, imaging and communications. Among the metasurfaces that have been found to exhibit the new effect are planar metamaterials featuring a continuous periodic zigzag pattern. The reported samples were designed to operate in the near-IR part of the spectrum and composed of arrays of continuous zigzag nano-wires, as well as their inversion, i.e., continuous zigzag nano-slits, covering the area of ~20x20µm2. The measured data suggest that these apparently trivial metasurfaces, while non-diffracting, can indeed behave differently under spatially incoherent and coherent illumination. The systematic experimental investigation and rigorous theoretical analysis of this phenomenon (the results of which will be presented at the conference) reveal that the effect is underpinned by strongly non-local response of the metasurfaces. Its mechanism involves interference of light scattered via non-dispersive delocalised plasmon modes uniquely supported by the fabric of the metasurfaces
Non-diffracting metallic metasurfaces with high directional sensitivity
No full textCompact optical elements capable of admitting/rejecting light from a specific direction(s) are key components of integrated systems for all-optical imaging processing, wavefront manipulation, optical communication in turbid media and optical metrology (and LIDARs in particular). The existing solutions based on spatially dispersive structures, such as photonic crystal slabs, resonant gratings, and perforated films exhibiting extraordinary transmission, all suffer from diffraction into multipole orders, while angular dependence of their response is complicated by consistent large wavelength shifts of the relevant spectral features [1] , [2] . Similar behaviour (although in the absence of multipole diffraction orders) is characteristic of recently demonstrated non-diffracting wavevector selective metasurfaces [3] , [4] . Here we identify and investigate a new, special class of such metasurfaces, in which the optical transmission spectra exhibit a strong amplitude correlation with the angle of incidence with the relevant changes confined to a very narrow wavelength range
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