15 research outputs found

    JOKARUS - Design of a compact optical iodine frequency reference for a sounding rocket mission

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    We present the design of a compact absolute optical frequency reference for space applications based on hyperfine transitions in molecular iodine with a targeted fractional frequency instability of better than 310143\cdot 10^{-14}. It is based on a micro-integrated extended cavity diode laser with integrated optical amplifier, fiber pigtailed second harmonic generation wave-guide modules, and a quasi-monolithic spectroscopy setup with operating electronics. The instrument described here is scheduled for launch end of 2017 aboard the TEXUS 54 sounding rocket as an important qualification step towards space application of iodine frequency references and related technologies. The payload will operate autonomously and its optical frequency will be compared to an optical frequency comb during its space flight

    Dynamics of micro-integrated external-cavity diode lasers: Simulations, analysis and experiments

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    This paper reports the results of numerical and experimental investigations of the dynamics of an external cavity diode laser device composed of a semiconductor laser and a distant Bragg grating, which provides an optical feedback. Due to the influence of the feedback, this system can operate at different dynamic regimes. The traveling wave model is used for simulations and analysis of the nonlinear dynamics in the considered laser device. Based on this model, a detailed analysis of the optical modes is performed, and the stability of the stationary states is discussed. It is shown, that the results obtained from the simulation and analysis of the device are in good agreement with experimental findings

    Early Neolithic executions indicated by clustered cranial trauma in the mass grave of Halberstadt

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    The later phase of the Central European Early Neolithic witnessed a rise in collective lethal violence to a level undocumented up to this date. This is evidenced by repeated massacres of settled communities of the Linearbandkeramik (ca. 5600-4900 cal bc), the first full farming culture in this area. Skeletal remains of several dozen victims of this prehistoric warfare are known from different sites in Germany and Austria. Here we show that the mass grave of Halberstadt, Germany, a new mass fatality site from the same period, reveals further and so far unknown facets of Early Neolithic collective lethal violence. A highly selected, almost exclusively adult male and non-local population sample was killed by targeted blows to the back of the head, indicating a practice of systematic execution under largely controlled conditions followed by careless disposal of the bodies. This discovery significantly increases current knowledge about warfare-related violent behaviour in Early Neolithic Central Europe

    A Dual-Species Atom Interferometer Payload for Operation on Sounding Rockets

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    We report on the design and the construction of a sounding rocket payload capable of performing atom interferometry with Bose-Einstein condensates of 41 K and 87 Rb. The apparatus is designed to be launched in two consecutive missions with a VSB-30 sounding rocket and is qualified to withstand the expected vibrational loads of 1.8 g root-mean-square in a frequency range between 20–2000 Hz and the expected static loads during ascent and re-entry of 25 g. We present a modular design of the scientific payload comprising a physics package, a laser system, an electronics system and a battery module. A dedicated on-board software provides a largely automated process of predefined experiments. To operate the payload safely in laboratory and flight mode, a thermal control system and ground support equipment has been implemented and will be presented. The payload presented here represents a cornerstone for future applications of matter wave interferometry with ultracold atoms on satellites

    The Bose-Einstein Condensate and Cold Atom Laboratory

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    © 2020, The Author(s). Microgravity eases several constraints limiting experiments with ultracold and condensed atoms on ground. It enables extended times of flight without suspension and eliminates the gravitational sag for trapped atoms. These advantages motivated numerous initiatives to adapt and operate experimental setups on microgravity platforms. We describe the design of the payload, motivations for design choices, and capabilities of the Bose-Einstein Condensate and Cold Atom Laboratory (BECCAL), a NASA-DLR collaboration. BECCAL builds on the heritage of previous devices operated in microgravity, features rubidium and potassium, multiple options for magnetic and optical trapping, different methods for coherent manipulation, and will offer new perspectives for experiments on quantum optics, atom optics, and atom interferometry in the unique microgravity environment on board the International Space Station

    The Bose-Einstein Condensate and Cold Atom Laboratory

    Get PDF
    Microgravity eases several constraints limiting experiments with ultracold andcondensed atoms on ground. It enables extended times of flight withoutsuspension and eliminates the gravitational sag for trapped atoms. Theseadvantages motivated numerous initiatives to adapt and operate experimentalsetups on microgravity platforms. We describe the design of the payload,motivations for design choices, and capabilities of the Bose-Einstein Condensateand Cold Atom Laboratory (BECCAL), a NASA-DLR collaboration. BECCALbuilds on the heritage of previous devices operated in microgravity, featuresrubidium and potassium, multiple options for magnetic and optical trapping,different methods for coherent manipulation, and will offer new perspectives forexperiments on quantum optics, atom optics, and atom interferometry in theunique microgravity environment on board the International Space Station
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