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Subject: Cryogenics ×

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Now showing 1 - 3 of 3
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    Multiple lobes in the far-field distribution of terahertz quantum-cascade lasers due to self-interference
    (New York : American Institute of Physics, 2016) Röben, B.; Wienold, M.; Schrottke, L.; Grahn, H.T.
    The far-field distribution of the emission intensity of terahertz (THz) quantumcascade lasers (QCLs) frequently exhibits multiple lobes instead of a single-lobed Gaussian distribution. We show that such multiple lobes can result from selfinterference related to the typically large beam divergence of THz QCLs and the presence of an inevitable cryogenic operation environment including optical windows. We develop a quantitative model to reproduce the multiple lobes. We also demonstrate how a single-lobed far-field distribution can be achieved.
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    Cryogenic characterization of a LiAlO 2 crystal and new results on spin-dependent dark matter interactions with ordinary matter: CRESST Collaboration
    (Berlin ; Heidelberg : Springer, 2020) Abdelhameed, A.H.; Angloher, G.; Bauer, P.; Bento, A.; Bertoldo, E.; Breier, R.; Bucci, C.; Canonica, L.; D’Addabbo, A.; Di Lorenzo, S.; Erb, A.; Feilitzsch, F.V.; Iachellini, N.F.; Fichtinger, S.; Fuchs, D.; Fuss, A.; Ghete, V.M.; Garai, A.; Gorla, P.; Hauff, D.; Ješkovský, M.; Jochum, J.; Kaizer, J.; Kaznacheeva, M.; Kinast, A.; Kluck, H.; Kraus, H.; Langenkämper, A.; Mancuso, M.; Mokina, V.; Mondragon, E.; Olmi, M.; Ortmann, T.; Pagliarone, C.; Palušová, V.; Pattavina, L.; Petricca, F.; Potzel, W.; Povinec, P.; Pröbst, F.; Reindl, F.; Rothe, J.; Schäffner, K.; Schieck, J.; Schipperges, V.; Schmiedmayer, D.; Schönert, S.; Schwertner, C.; Stahlberg, M.; Stodolsky, L.; Strandhagen, C.; Strauss, R.; Usherov, I.; Wagner, F.; Willers, M.; Zema, V.; Zeman, J.; Brützam, M.; Ganschow, S.
    In this work, a first cryogenic characterization of a scintillating LiAlO 2 single crystal is presented. The results achieved show that this material holds great potential as a target for direct dark matter search experiments. Three different detector modules obtained from one crystal grown at the Leibniz-Institut für Kristallzüchtung (IKZ) have been tested to study different properties at cryogenic temperatures. Firstly, two 2.8 g twin crystals were used to build different detector modules which were operated in an above-ground laboratory at the Max Planck Institute for Physics (MPP) in Munich, Germany. The first detector module was used to study the scintillation properties of LiAlO 2 at cryogenic temperatures. The second achieved an energy threshold of (213.02 ± 1.48) eV which allows setting a competitive limit on the spin-dependent dark matter particle-proton scattering cross section for dark matter particle masses between 350MeV/c2 and 1.50GeV/c2. Secondly, a detector module with a 373 g LiAlO 2 crystal as the main absorber was tested in an underground facility at the Laboratori Nazionali del Gran Sasso (LNGS): from this measurement it was possible to determine the radiopurity of the crystal and study the feasibility of using this material as a neutron flux monitor for low-background experiments. © 2020, The Author(s).
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    Nanofiber-based high-Q microresonator for cryogenic applications
    (Washington, DC : Soc., 2020) Hütner, Johanna; Hoinkes, Thomas; Becker, Martin; Rothhardt, Manfred; Rauschenbeute, Arno; Skoff, Sarah M.
    We demonstrate a cryo-compatible, fully fiber-integrated, alignment-free optical microresonator. The compatibility with low temperatures expands its possible applications to the wide field of solid-state quantum optics, where a cryogenic environment is often a requirement. At a temperature of 4.6 K we obtain a quality factor of (9.9 ± 0.7) × 106. In conjunction with the small mode volume provided by the nanofiber, this cavity can be either used in the coherent dynamics or the fast cavity regime, where it can provide a Purcell factor of up to 15. Our resonator is therefore suitable for significantly enhancing the coupling between light and a large variety of different quantum emitters and due to its proven performance over a wide temperature range, also lends itself for the implementation of quantum hybrid systems. © 2020 OSA - The Optical Society. All rights reserved.