. (2013) A surface-patterned chip as a strong source of ultracold atoms for quantum technologies. Nature Nanotechnology, 8 (5). pp. 321-324. Copyright © 2013 MacMillanA copy can be downloaded for personal non-commercial research or study, without prior permission or chargeThe content must not be changed in any way or reproduced in any format or medium without the formal permission of the copyright holder(s) Laser cooled atoms are central to modern precision measurements 1-6 . They are also increasingly important as an enabling technology for experimental cavity quantum electrodynamics 7,8 , quantum information processing 9-11 and matter wave interferometry 12 . Although significant progress has been made in miniaturising atomic metrological devices 13,14 , these are limited in accuracy by their use of hot atomic ensembles and buffer gases. Advances have also been made in producing portable apparatus that benefit from the advantages of atoms in the microKelvin regime 15,16 . However, simplifying atomic cooling and loading using microfabrication technology has proved difficult 17,18 . In this letter we address this problem, realising an atom chip that enables the integration of laser cooling and trapping into a compact apparatus. Our source delivers ten thousand times more atoms than previous magneto-optical traps with microfabricated optics and, for the first time, at sub-Doppler temperatures. Moreover, the same chip design offers a simple way to form stable optical lattices. These features, combined with the simplicity of fabrication and the ease of operation, make these new traps a key advance in the development of cold-atom technology for high-accuracy, portable measurement devices.

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The generation, measurement, and manipulation of light at the single-and few-photon levels underpin a rapidly expanding range of applications. These range from applications moving into the few-photon regime in order to achieve improved sensitivity and/or energy efficiency, as well as new applications that operate solely in this regime, such as quantum key distribution and physical quantum random number generation. There is intensive research to develop new quantum optical technologies, for example, quantum sensing, simulation, and computing. These applications rely on the performance of the single-photon sources and detectors they employ; this review article gives an overview of the methods, both conventional and recently developed, that are available for measuring the performance of these devices, with traceability to the SI system. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

The coherent control of quantum-entangled states of trapped ions has led to significant advances in quantum information, quantum simulation, quantum metrology and laboratory tests of quantum mechanics and relativity. All of the basic requirements for processing quantum information with arrays of ion-based quantum bits (qubits) have been proven in principle. However, so far, no more than 14 ion-based qubits have been entangled with the ion-trap approach, so there is a clear need for arrays of ion traps that can handle a much larger number of qubits. Traps consisting of a two-dimensional electrode array have undergone significant development, but three-dimensional trap geometries can create a superior confining potential. However, existing three-dimensional approaches, as used in the most advanced experiments with trap arrays, cannot be scaled up to handle greatly increased numbers of ions. Here, we report a monolithic three-dimensional ion microtrap array etched from a silica-on-silicon wafer using conventional semiconductor fabrication technology. We have confined individual (88)Sr(+) ions and strings of up to 14 ions in a single segment of the array. We have measured motional frequencies, ion heating rates and storage times. Our results demonstrate that it should be possible to handle several tens of ion-based qubits with this approach.

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