Entity

Time filter

Source Type

Muri, Switzerland

Politi A.,University of Bristol | Matthews J.C.F.,University of Bristol | Laing A.,University of Bristol | Peruzzo A.,University of Bristol | And 10 more authors.
Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference: 2010 Laser Science to Photonic Applications, CLEO/QELS 2010 | Year: 2010

Quantum technologies based on photons will likely require integrated optics architectures for improved performance, miniaturization and scalability. We demonstrate highfidelity silica-on-silicon integrated optical realizations of key quantum photonic circuits and the first integrated quantum algorithm. © 2009 Optical Society of America.


Welti A.,ETH Zurich | Kanji Z.A.,ETH Zurich | Luond F.,Federal Office of Metrology | Stetzer O.,ETH Zurich | Lohmann U.,ETH Zurich
Journal of the Atmospheric Sciences | Year: 2014

To identify the temperature and humidity conditions at which different ice nucleation mechanisms are active, the authors conducted experiments on 200-, 400-, and 800-nm size-selected kaolinite particles, exposing them to temperatures between 218 and 258Kand relative humidities with respect to ice (RHi) between 100% and 180%, including the typical conditions for cirrus and mixed-phase-cloud formation. Measurements of the ice active particle fraction as a function of temperature and relative humidity with respect to ice are eported. The authors find enhanced activated fractions when water saturation is reached at mixed-phasecloud temperatures between 235 and 241K and a distinct increase in the activated fraction below 235K at conditions below water saturation. To provide a functional description of the observed ice nucleation mechanisms, the experimental results are analyzed by two different particle-surface models within the framework of classical nucleation theory. Describing the ice nucleation activity of kaolinite particles by assuming deposition nucleation to be the governing mechanism below water saturation was found to be inadequate to represent the experimental data in the whole temperature range investigated. The observed increase in the activated fraction below water saturation and temperatures below 235K corroborate the assumption that an appreciable amount of adsorbed or capillary condensed water is present on kaolinite particles, which favors ice nucleation. © 2014 American Meteorological Society.


Di Domenico G.,University Of Neuchtel | Devenoges L.,University Of Neuchtel | Joyet A.,University Of Neuchtel | Stefanov A.,Federal Office of Metrology | Thomann P.,University Of Neuchtel
Proceedings of the IEEE International Frequency Control Symposium and Exposition | Year: 2011

The continuous atomic fountain primary frequency standard FOCS-2 is quite unique since all the atomic fountain clocks presently contributing to the international atomic time (TAI) are operating in pulsed mode [1]. Our alternative approach offers the possibility to operate with a high atomic flux without the collisional shift limiting the accuracy or the Dick effect limiting the stability when a quartz is used as local oscillator [2], [3]. Moreover, it contributes to the metrological diversity since the relative importance of the error budget contributors is different in the two types of fountains, notably for microwave cavity and density related effects. In this contribution we present the status of the metrological evaluation of the continuous fountain FOCS-2. Thanks to an innovative atomic beam source followed by an atomic state preparation stage, we reach a signal-to-noise ratio of 600√Hz and thus a relative frequency instability of 6 × 10-14 T-1/2. A detailed investigation of the frequency shifts which are specific to the continuous operation (light-shift from the source and cavity end-to-end phase shift) shows that the continuous fountain is compatible with an inaccuracy at the 10-15 level or below. © 2011 IEEE.


Gilbert O.,French National Laboratory of Metrology and Testing | Bielsa F.,French National Laboratory of Metrology and Testing | Juncar P.,Institute National Of Metrologie Lne Inm Cnam | Eichenberger A.,Federal Office of Metrology | Geneves G.,French National Laboratory of Metrology and Testing
CPEM Digest (Conference on Precision Electromagnetic Measurements) | Year: 2010

The alignment of optical devices such as interferometers and laser position detectors is needed for the different adjustments of watt balances. This paper describes the optical apparatus and the numerical simulations developed to tune the alignment of experimental setup. A telescope coupled with a CCD camera and data processing are presented in detail. © 2010 IEEE.


Bielsa F.,French National Laboratory of Metrology and Testing | Eichenberger A.,Federal Office of Metrology | Gilbert O.,French National Laboratory of Metrology and Testing | Juncar P.,Institute National Of Metrologie Lne Inm Cnam | Geneves G.,French National Laboratory of Metrology and Testing
CPEM Digest (Conference on Precision Electromagnetic Measurements) | Year: 2010

In watt balance experiments, the determination of the position and the velocity of a moving coil have a crucial contribution in the overall uncertainty. In this paper, we present optical devices that will be set up to measure the two above mentioned parameters © 2010 IEEE.

Discover hidden collaborations