Kaldewey Timo, Lueker Sebastian, Kuhlmann Andreas V., Valentin Sascha R., Ludwig Arne, Wieck Andreas D., Reiter Doris E., Kuhn Tilmann, Warburton Richard J. (2017), Coherent and robust high-fidelity generation of a biexciton in a quantum dot by rapid adiabatic passage, in PHYSICAL REVIEW B
, 95(16), 161302(R).
Kaldewey Timo, Lueker Sebastian, Kuhlmann Andreas V., Valentin Sascha R., Chauveau Jean-Michel, Ludwig Arne, Wieck Andreas D., Reiter Doris E., Kuhn Tilmann, Warburton Richard J. (2017), Demonstrating the decoupling regime of the electron-phonon interaction in a quantum dot using chirped optical excitation, in PHYSICAL REVIEW B
, 95(24), 241306.
Najer Daniel, Renggli Martina, Riedel Daniel, Starosielec Sebastian, Warburton Richard J. (2017), Fabrication of mirror templates in silica with micron-sized radii of curvature, in APPLIED PHYSICS LETTERS
, 110(1), 011101.
Munsch Mathieu, Kuhlmann Andreas V., Cadeddu Davide, Gerard Jean-Michel, Claudon Julien, Poggio Martino, Warburton Richard J. (2017), Resonant driving of a single photon emitter embedded in a mechanical oscillator, in NATURE COMMUNICATIONS
, 8, 76.
Wolters Janik, Buser Gianni, Horsley Andrew, Beguin Lucas, Jockel Andreas, Jahn Jan-Philipp, Warburton Richard J., Treutlein Philipp (2017), Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons, in PHYSICAL REVIEW LETTERS
, 119(6), 060502.
Cadeddu Davide, Teissier Jean, Braakman Floris R., Gregersen Niels, Stepanov Petr, Gerard Jean-Michel, Claudon Julien, Warburton Richard J., Poggio Martino, Munsch Mathieu (2016), A fiber-coupled quantum-dot on a photonic tip, in APPLIED PHYSICS LETTERS
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Heath Robert M., Tanner Michael G., Kirkwood Robert A., Miki Shigehito, Warburton Richard J., Hadfield Robert H. (2016), A tunable fiber-coupled optical cavity for agile enhancement of detector absorption, in JOURNAL OF APPLIED PHYSICS
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Prechtel Jonathan H., Kuhlmann Andreas V., Houel Julien, Ludwig Arne, Valentin Sascha R., Wieck Andreas D., Warburton Richard J. (2016), Decoupling a hole spin qubit from the nuclear spins, in NATURE MATERIALS
, 15(9), 981-986.
Wuest Gunter, Munsch Mathieu, Maier Franziska, Kuhlmann Andreas V., Ludwig Arne, Wieck Andreas D., Loss Daniel, Poggio Martino, Warburton Richard J. (2016), Role of the electron spin in determining the coherence of the nuclear spins in a quantum dot, in NATURE NANOTECHNOLOGY
, 11(10), 885-885.
Jahn Jan-Philipp, Munsch Mathieu, Beguin Lucas, Kuhlmann Andreas V., Renggli Martina, Huo Yongheng, Ding Fei, Trotta Rinaldo, Reindl Marcus, Schmidt Oliver G., Rastelli Armando, Treutlein Philipp, Warburton Richard J. (2015), An artificial Rb atom in a semiconductor with lifetime-limited linewidth, in PHYSICAL REVIEW B
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Prechtel Jonathan H., Maier Franziska, Houel Julien, Kuhlmann Andreas V., Ludwig Arne, Wieck Andreas D., Loss Daniel, Warburton Richard J. (2015), Electrically tunable hole g factor of an optically active quantum dot for fast spin rotations, in PHYSICAL REVIEW B
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Greuter Lukas, Najer Daniel, Kuhlmann Andreas V., Valentin Sascha R., Ludwig Arne, Wieck Andreas D., Starosielec Sebastian, Warburton Richard J. (2015), Epitaxial lift-off for solid-state cavity quantum electrodynamics, in JOURNAL OF APPLIED PHYSICS
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Greuter Lukas, Starosielec Sebastian, Kuhlmann Andreas V., Warburton Richard J. (2015), Towards high-cooperativity strong coupling of a quantum dot in a tunable microcavity, in PHYSICAL REVIEW B
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Kuhlmann Andreas V., Prechtel Jonathan H., Houel Julien, Ludwig Arne, Reuter Dirk, Wieck Andreas D., Warburton Richard J. (2015), Transform-limited single photons from a single quantum dot, in NATURE COMMUNICATIONS
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Riedel D., Rohner D., Ganzhorn M., Kaldewey T., Appel P., Neu E., Warburton R. J., Maletinsky P. (2014), Low-Loss Broadband Antenna for Efficient Photon Collection from a Coherent Spin in Diamond, in PHYSICAL REVIEW APPLIED
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Semiconductor heterostructures have uniquely attractive properties for electronics and opto-electronics. Semiconductors underpin information processing: electronic signals are manipulated at GHz frequencies and transmitted over large distances via optical fibres using semiconductor lasers and detectors. Potentially, these material advantages can be exploited in the creation of quantum devices which manipulate individual quantum states. Proposals exist in the areas of communication, metrology, imaging and information processing. An optically active semiconductor quantum dot is not just a potentially excellent single photon source but also a versatile host for a spin qubit. In fact optical techniques allow spin initialization, ultra-fast manipulation and single shot read-out. The performance however is limited by noise. Independent of quantum applications, understanding the qubit-environment interaction enables some core issues in condensed matter physics to be profitably revisited now that exquisite experiments can be performed on the nano-scale. One stumbling block to the successful application of a quantum dot spin as qubit is the loss of spin coherence via the hyperfine interaction with the nuclear spins of the host material, a central spin problem. In a quantum dot, the nuclear spin ensemble has a nano-scale and the breakdown of the Markov approximation leads to some unusual physics. This project aims to manipulate the nuclear spins in just one quantum dot with nuclear magnetic resonance (NMR) techniques. The central idea is to use NMR with frequency-swept pulses such that each nuclear spin, independent of the particular isotope or its exact quadrupole frequency, is addressed at some point in the frequency sweep. The physics focusses on adiabaticity versus Landau-Zener tunneling for manipulation, and Stueckelberg oscillations as a signature of quantum coherence. In particular, the aim is to determine the chemical composition, the nuclear spin temperature following laser-cooling, the quadrupole frequency distribution of all the main isotopes, and the nuclear spin coherence times. Additionally, the proposal involves determining and understanding the nuclear spin noise for electron spin, hole spin and exciton qubits. A hole spin is a particularly interesting case: the hyperfine interaction has a simple and benign form for a pure heavy-hole spin. The true hyperfine interaction for a real hole spin is unknown and the issue is surrounded by controversy. This project aims to determine all the key terms in the hole spin hyperfine interaction with a view to optimizing the spin coherence.A second stumbling block is the wavelength: semiconductor single photon sources presently emit in no-man's land, at wavelengths too short for efficient transport through an optical fibre but too short for compatibility with other quantum systems. One very attractive quantum system is Rb. Laser-cooled Rb atoms are very dense resulting in large photon absorption probabilities, extraordinarily cold resulting in long coherence times, and represent an ideal quantum system. A single Rb atom is however an inconvenient single photon source: single atom trapping is challenging, and the flux is low on account of the long spontaneous emission time. Conversely, a single quantum dot has the potential to become a robust, high-flux and narrow linewidth emitter of single photons, properties not shared by any other emitter. The aim here is to develop a single "droplet" quantum dot as an excellent single photon source at the Rb wavelength, 780 nm. A quantum dot single photon will be created, stored in an ultra-cold gas of Rb atoms, and subsequently re-created with a laser pulse, a prototype hybrid quantum memory. The particular challenges centre around the development of the droplet quantum dots and the associated heterostructures. An overriding issue for all these activities is the poor photon extraction efficiency from the high index semiconductor. This will be addressed here by engineering the photon modes, both with waveguides and, notably, with tunable micro-cavities. The tunable micro-cavities are particularly attractive: routes to achieving spin-resolved strong coupling between the quantum dot and vacuum cavity field are presented.