Stefan Alaric Schäffer

Stefan Alaric Schäffer

Postdoc


  1. 2024
  2. Published

    Collectively enhanced Ramsey readout by cavity sub- to superradiant transition

    Bohr, Eliot, Kristensen, Sofus Laguna, Hotter, C., Schäffer, Stefan Alaric, Robinson-Tait, J. C., Thomsen, Jan Westenkær, Zelevinsky, T., Ritsch, H. & Müller, Jörg Helge, 5 Feb 2024, In: Nature Communications. 15, 7 p., 1084.

    Research output: Contribution to journalJournal articlepeer-review

  3. 2022
  4. Published

    Prospects of a superradiant laser based on a thermal or guided beam of 88Sr

    Tang, M., Schäffer, Stefan Alaric & Müller, Jörg Helge, 9 Dec 2022, In: Physical Review A. 106, 6, 10 p., 063704.

    Research output: Contribution to journalJournal articlepeer-review

  5. 2021
  6. Towards an Active Optical Clock using an Optical Conveyor within a Ring Cavity

    Kazakov, G., Dubey, S., Fama, F., Zhou, Z. S., Beli Silva, C., Schäffer, Stefan Alaric, Bennetts, S. & Schreck, F., 7 Jul 2021, 2021 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium, EFTF/IFCS 2021 - Proceedings. Gainesville, Fl, USA: IEEE, Vol. 21403938.

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

  7. Frequency ratio measurements at 18-digit accuracy using an optical clock network

    Boulder Atomic Clock Optical Network (BACON) Collaboration*, B. A. C. O. N. (. C., 25 Mar 2021, In: Nature. 591, 7851, p. 564-569 6 p.

    Research output: Contribution to journalJournal articlepeer-review

  8. 2020
  9. Optical atomic clock comparison through turbulent air

    Bodine, M. I., Deschênes, J. D., Khader, I. H., Swann, W. C., Leopardi, H., Beloy, K., Bothwell, T., Brewer, S. M., Bromley, S. L., Chen, J. S., Diddams, S. A., Fasano, R. J., Fortier, T. M., Hassan, Y. S., Hume, D. B., Kedar, D., Kennedy, C. J., Koepke, A., Leibrandt, D. R., Ludlow, A. D. & 15 others, Mcgrew, W. F., Milner, W. R., Nicolodi, D., Oelker, E., Parker, T. E., Robinson, J. M., Romish, S., Schäffer, Stefan Alaric, Sherman, J. A., Sonderhouse, L., Yao, J., Ye, J., Zhang, X., Newbury, N. R. & Sinclair, L. C., Sep 2020, In: Physical Review Research. 2, 3, 033395.

    Research output: Contribution to journalJournal articlepeer-review

  10. 10-18 optical atomic clock comparisons within the boulder atomic clock network

    Nardelli, N. V., Beloy, K., Bodine, M. I., Bothwell, T., Brewer, S., Bromley, S., Clements, E., Deschenes, J. D., Diddams, S. A., Fasano, R., Fortier, T. M., Hassan, Y., Hume, D. H., Kedar, D., Kennedy, C. J., Khader, I., Koepke, A., Leibrandt, D. R., Leopardi, H., Ludlow, A. & 13 others, McGrew, W. F., Milner, W., Newbury, N., Nicolodi, D., Oelker, E., Parker, T., Robinson, J. M., Schäffer, Stefan Alaric, Sherman, J. A., Sinclair, L. C., Sonderhouse, L., Swann, W. C. & Wineland, D. J., 15 May 2020, In: Cleo. F183, STh3G.3.

    Research output: Contribution to journalConference articlepeer-review

  11. Published

    AEDGE: Atomic Experiment for Dark Matter and Gravity Exploration in Space

    El-Neaj, Y. A., Alpigiani, C., Amairi-Pyka, S., Araujo, H., Balaz, A., Belic, A., Bentine, E., Bernabeu, J., Bingham, R., Bolpasi, V., Bowden, W., Buchmueller, O., Burrage, C., Calmet, X., Canuel, B., Charmandaris, V., Chen, X., Coleman, J., Cotter, J., Cui, Y. & 69 others, Derevianko, A., De Roeck, A., Drougkakis, I., Dutan, I., Elertas, G., Ellis, J., El Sawy, M., Fassi, F., Felea, D., Feng, C., Flack, R., Foot, C., Fuentes, I., Gaaloul, N., Gauguet, A., Geiger, R., Gibson, V., Giudice, G., Goldwin, J., Grachov, O., Graham, P. W., Grasso, D., Van der Grinten, M., Guendogan, M., Haehnelt, M. G., Harte, T., Hees, A., Hobson, R., Hogan, J., Holst, B., Holynski, M., Kasevich, M., Kavanagh, B. J., Von Klitzing, W., Kovachy, T., Krikler, B., Krutzik, M., Lewicki, M., Lien, Y., Liu, M., Luciano, G. G., Pandey, S., Paternostro, M., Penning, B., Peters, A., Prevedelli, M., Puthiya-Veettil, V., Quenby, J., Rasel, E., Roura, A., Sabulsky, D., Sameed, M., Sauer, B., Schäffer, Stefan Alaric, Schiller, S., Schkolnik, V., Schlippert, D., Schubert, C., Sfar, H. R., Shayeghi, A., Soares-Santos, M., Vasilakis, G., Vaskonen, V., Vogt, C., Webber-Date, A., Windpassinger, P., Woltmann, M., Yazgan, E. & Zupan, J., 4 Mar 2020, In: EPJ Quantum Technology. 7, 1, 27 p., 6.

    Research output: Contribution to journalJournal articlepeer-review

  12. Published

    Lasing on a narrow transition in a cold thermal strontium ensemble

    Schäffer, Stefan Alaric, Tang, M., Henriksen, M. R., Jørgensen, Asbjørn Arvad, Christensen, B. T. R. & Thomsen, Jan Westenkær, 17 Jan 2020, In: Physical Review A. 101, 1, 9 p., 013819.

    Research output: Contribution to journalJournal articlepeer-review

  13. 2019
  14. Optical-Clock-Based Time Scale

    Yao, J., Sherman, J. A., Fortier, T., Leopardi, H., Parker, T. E., McGrew, W., Zhang, X., Nicolodi, D., Fasano, R., Schäffer, Stefan Alaric, Beloy, K., Savory, J., Romisch, S., Oates, C., Diddams, S., Ludlow, A. D. & Levine, J., 30 Oct 2019, In: Physical Review Applied. 12, 4, 10 p., 044069.

    Research output: Contribution to journalJournal articlepeer-review

  15. Published

    Towards the optical second: verifying optical clocks at the SI limit

    McGrew, W. F., Zhang, X., Leopardi, H., Fasano, R. J., Nicolodi, D., Beloy, K., Yao, J., Sherman, J. A., Schäffer, Stefan Alaric, Savory, J., Brown, R. C., Romisch, S., Oates, C. W., Parker, T. E., Fortier, T. M. & Ludlow, A. D., 20 Apr 2019, In: Optica. 6, 4, p. 448-454

    Research output: Contribution to journalJournal articlepeer-review

  16. Published

    Cavity-enhanced optical clocks

    Schäffer, Stefan Alaric, 2019, Niels Bohr Institute, Faculty of Science, University of Copenhagen.

    Research output: Book/ReportPh.D. thesis

  17. 2018
  18. Published

    Atomic clock performance enabling geodesy below the centimetre level

    McGrew, W. F., Zhang, X., Fasano, R. J., Schäffer, Stefan Alaric, Beloy, K., Nicolodi, D., Brown, R. C., Hinkley, N., Milani, G., Schioppo, M., Yoon, T. H. & Ludlow, A. D., 6 Dec 2018, In: Nature. 564, 7734, p. 87-90

    Research output: Contribution to journalJournal articlepeer-review

  19. Published

    Det aktive atomur - en laser i sin reneste form

    Tang, M. & Schäffer, Stefan Alaric, 1 Dec 2018, In: Kvant. 4, p. 20-23

    Research output: Contribution to journalJournal article

  20. Published

    Progress on optical- clock-based time scale at NIST: Simulations and preliminary real-data analysis

    Yao, J., Sherman, J., Fortier, T., Leopardi, H., Parker, T., Levine, J., Savory, J., Romisch, S., McGrew, W., Zhang, X., Nicolodi, D., Fasano, R., Schäffer, Stefan Alaric, Beloy, K. & Ludlow, A., 19 Sep 2018, In: Navigation. 248, p. 1-8

    Research output: Contribution to journalConference articlepeer-review

  21. Published

    Optical frequency measurements at 1x10(-18) uncertainty with ytterbium optical lattice clocks

    Ludlow, A. D., McGrew, W. F., Zhang, X., Nicolodi, D., Fasano, R. J., Schäffer, Stefan Alaric, Brown, R. C., Fox, R. W., Hinkley, N., Yoon, T. H. & Beloy, K., 8 Jul 2018, 2018 Conference on Precision Electromagnetic Measurements (CPEM). Paris, France: IEEE

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

  22. Published

    Faraday-Shielded dc Stark-Shift-Free Optical Lattice Clock

    Beloy, K., Zhang, X., McGrew, W. F., Hinkley, N., Yoon, T. H., Nicolodi, D., Fasano, R. J., Schäffer, Stefan Alaric, Brown, R. C. & Ludlow, A. D., 2 May 2018, In: Physical Review Letters. 120, 18, 5 p., 183201.

    Research output: Contribution to journalJournal articlepeer-review

  23. Published

    Incorporating an Optical Clock into a Time Scale at NIST: Simulations and Preliminary Real-Data Analysis

    Sherman, J., Fortier, T., Yao, J., Parker, J., Levine, T., Savory, J., Romisch, S., McGrew, W., Zhang, X., Nicolodi, D., Fasano, R., Schäffer, Stefan Alaric, Beloy, K. & Ludlow, A., 29 Jan 2018, Proceedings of the 49th Annual Precise Time and Time Interval Systems and Applications Meeting. Reston, Virginia : Wiley, p. 11-21

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

  24. 2017
  25. Published

    Dynamics of bad-cavity-enhanced interaction with cold Sr atoms for laser stabilization

    Schäffer, Stefan Alaric, Christensen, B. T. R., Henriksen, M. R. & Thomsen, Jan Westenkær, 24 Jul 2017, In: Physical Review A. 96, 1, 013847.

    Research output: Contribution to journalJournal articlepeer-review

  26. Published

    Towards passive and active laser stabilization using cavity-enhanced atomic interaction

    Schäffer, Stefan Alaric, Christensen, B. T. R., Rathmann, S. M., Appel, Martin Hayhurst, Henriksen, M. R. & Thomsen, Jan Westenkær, 19 Jun 2017, In: Journal of Physics - Conference Series. 810, 1, 7 p., 012002.

    Research output: Contribution to journalJournal articlepeer-review

  27. 2015
  28. Published

    Nonlinear spectroscopy of Sr atoms in an optical cavity for laser stabilization

    Christensen, B. T. R., Henriksen, M. R., Schäffer, Stefan Alaric, Westergaard, P. G., Ye, J., Holland, M. & Thomsen, Jan Westenkær, 6 Nov 2015, In: Physical Review A (Atomic, Molecular and Optical Physics). 92, 053820.

    Research output: Contribution to journalJournal articlepeer-review

  29. Published

    Towards Molecular Clocks Using Large Waist Cavity Enhanced Spectroscopy: FACT workshop

    Adsersen, S. S., Henriksen, M. R., Schäffer, Stefan Alaric & Thomsen, Jan Westenkær, 1 Sep 2015

    Research output: Other contributionResearch

  30. Published

    Large waist cavity for ultra-narrow transition spectroscopy

    Schäffer, Stefan Alaric, Adsersen, S. S., Christensen, B. T. R. & Thomsen, Jan Westenkær, 12 Apr 2015, 2015 Joint Conference of the IEEE International Frequency Control Symposium & the European Frequency and Time Forum . IEEE ed. Denver,CO, p. 625-629 15285778. (IEEE International Frequency Control Symposium & the European Frequency and Time Forum; No. 15285778).

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

  31. Published

    Laser stabilization on velocity dependent nonlinear dispersion of Sr atoms in an optical cavity: In Frequency Control Symposium & the European Frequency and Time Forum

    Christensen, B. T. R., Schäffer, Stefan Alaric, Henriksen, M. R., Westergaard, P. G., Ye, J. & Thomsen, Jan Westenkær, 10 Apr 2015, In: Proceedings of the IEEE. p. 357-362

    Research output: Contribution to journalConference articlepeer-review

ID: 143261181