6,764 research outputs found
Optimal antibunching in passive photonic devices based on coupled nonlinear resonators
We propose the use of weakly nonlinear passive materials for prospective
applications in integrated quantum photonics. It is shown that strong
enhancement of native optical nonlinearities by electromagnetic field
confinement in photonic crystal resonators can lead to single-photon generation
only exploiting the quantum interference of two coupled modes and the effect of
photon blockade under resonant coherent driving. For realistic system
parameters in state of the art microcavities, the efficiency of such
single-photon source is theoretically characterized by means of the
second-order correlation function at zero time delay as the main figure of
merit, where major sources of loss and decoherence are taken into account
within a standard master equation treatment. These results could stimulate the
realization of integrated quantum photonic devices based on non-resonant
material media, fully integrable with current semiconductor technology and
matching the relevant telecom band operational wavelengths, as an alternative
to single-photon nonlinear devices based on cavity-QED with artificial atoms or
single atomic-like emitters.Comment: to appear in New J. Physic
Dual-camera system for high-speed imaging in particle image velocimetry
Particle image velocimetry is an important technique in experimental fluid
mechanics, for which it has been essential to use a specialized high-speed
camera. However, the high speed is at the expense of other performances of the
camera, i.e., sensitivity and image resolution. Here, we demonstrate that the
high-speed imaging is also possible with a pair of still cameras.Comment: 4 pages, accepted by Journal of Visualization (see
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Radiation Risks and Mitigation in Electronic Systems
Electrical and electronic systems can be disturbed by radiation-induced
effects. In some cases, radiation-induced effects are of a low probability and
can be ignored; however, radiation effects must be considered when designing
systems that have a high mean time to failure requirement, an impact on
protection, and/or higher exposure to radiation. High-energy physics power
systems suffer from a combination of these effects: a high mean time to failure
is required, failure can impact on protection, and the proximity of systems to
accelerators increases the likelihood of radiation-induced events. This paper
presents the principal radiation-induced effects, and radiation environments
typical to high-energy physics. It outlines a procedure for designing and
validating radiation-tolerant systems using commercial off-the-shelf
components. The paper ends with a worked example of radiation-tolerant power
converter controls that are being developed for the Large Hadron Collider and
High Luminosity-Large Hadron Collider at CERN.Comment: 19 pages, contribution to the 2014 CAS - CERN Accelerator School:
Power Converters, Baden, Switzerland, 7-14 May 201
Silicon Atomic Quantum Dots Enable Beyond-CMOS Electronics
We review our recent efforts in building atom-scale quantum-dot cellular
automata circuits on a silicon surface. Our building block consists of silicon
dangling bond on a H-Si(001) surface, which has been shown to act as a quantum
dot. First the fabrication, experimental imaging, and charging character of the
dangling bond are discussed. We then show how precise assemblies of such dots
can be created to form artificial molecules. Such complex structures can be
used as systems with custom optical properties, circuit elements for
quantum-dot cellular automata, and quantum computing. Considerations on
macro-to-atom connections are discussed.Comment: 28 pages, 19 figure
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