Power scaling of extreme-ultraviolet frequency combs to the mW level per high-harmonic order

ORAL

Abstract

The extreme ultraviolet (XUV) presents a barely-explored region for precision spectroscopy studies with promising targets such as ground-state transitions in few-electron atoms and ions, and even nuclear transitions. Newly-developed XUV frequency combs can reach Hz-level linewidths, but their usefulness for precision spectroscopy has been limited by their low power. XUV frequency combs are produced via high-order harmonic generation (HHG) in a weakly-ionized gas medium driven by an intense IR laser. A high repetition rate ($\gg$10 MHz) is needed for stable frequency-comb operation, but the short time interval between consecutive laser pulses ($\ll$100 ns) leads to the accumulation of a high-density steady-state plasma which inhibits phase-matching of HHG, thus restricting the conversion efficiency. By heating the gas nozzle and seeding the heavy generation gas (xenon) in a light carrier gas (helium), we significantly increase the supersonic jet velocity, thus reducing the number of laser pulses that interact with the same atom/ion, reaching the single-pulse regime at 77 MHz repetition rate. We demonstrate phase-matched high-repetition-rate HHG for the first time, and generate 2 mW at 97 nm and 0.9 mW at 63 nm, surpassing previous XUV-comb power records by an order of magnitude.

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Authors

  • Stephen Schoun

    JILA, NIST and the University of Colorado, Boulder

  • Colin Roberts

    High Precision Devices, Boulder, CO, Raytheon, Tucson, AZ, Seagate Technology, Minneapolis, MN, Ball Aerospace (retired), Bloomfield, CO, New Mexico State University, Brigham Young University, Colorado State University, Heinrich-Heine-Universitat Dusseldorf, National Security Technologies, Universidad de Buenos Aires, Colorado State Univ, Colorado College, Utah State University, Advisor, Material Physics Group, Utah State University, Box Elder Innovations, LLC, JILA and Department of Physics, CU Boulder, JILA and Department of Mathematics, CU Boulder, Colorado State University, Fort Collins, Colorado 80523, USA, JILA, NIST and the University of Colorado, Boulder, NIST, University of Colorado / NIST, University of Colorado/JILA, Colorado Sch of Mines, Colorado School of Mines, Southwestern Indian Polytechnic Institute, UC-Berkeley, Colorado State University, Fort Collins, CO, Wroclaw University of Science and Technology, Wroclaw, Poland, JILA, University of Colorado and NIST, Harvard University and Harvard-MIT Center for Ultracold Atoms, Univ of Colorado - Boulder, USAFA, Univ of Denver, Boyce Research Initiatives and Educational Foundation, Brilliant Sky Observatory, San Diego Mesa College, Utah Valley University, University of Colorado Boulder, Brigham Young Univ - Provo, Oak Ridge National Laboratory, University of Sherbrooke, NIST Boulder, Universidad Complutense de Madrid, Electrical and Computer Engineering Department, Colorado State University, Fort Collins, Co 80525, Lawrence Livermore National Lab. (United States), Physics Department, Colorado State University, Fort Collins, Co 80525, JILA, Department of Physics, University of Colorado Boulder, Los Alamos National Laboratory, University of Alabama, University of Wyoming, University of Guelph, University of Guelph, Canadian Light source

  • Colin Roberts

    High Precision Devices, Boulder, CO, Raytheon, Tucson, AZ, Seagate Technology, Minneapolis, MN, Ball Aerospace (retired), Bloomfield, CO, New Mexico State University, Brigham Young University, Colorado State University, Heinrich-Heine-Universitat Dusseldorf, National Security Technologies, Universidad de Buenos Aires, Colorado State Univ, Colorado College, Utah State University, Advisor, Material Physics Group, Utah State University, Box Elder Innovations, LLC, JILA and Department of Physics, CU Boulder, JILA and Department of Mathematics, CU Boulder, Colorado State University, Fort Collins, Colorado 80523, USA, JILA, NIST and the University of Colorado, Boulder, NIST, University of Colorado / NIST, University of Colorado/JILA, Colorado Sch of Mines, Colorado School of Mines, Southwestern Indian Polytechnic Institute, UC-Berkeley, Colorado State University, Fort Collins, CO, Wroclaw University of Science and Technology, Wroclaw, Poland, JILA, University of Colorado and NIST, Harvard University and Harvard-MIT Center for Ultracold Atoms, Univ of Colorado - Boulder, USAFA, Univ of Denver, Boyce Research Initiatives and Educational Foundation, Brilliant Sky Observatory, San Diego Mesa College, Utah Valley University, University of Colorado Boulder, Brigham Young Univ - Provo, Oak Ridge National Laboratory, University of Sherbrooke, NIST Boulder, Universidad Complutense de Madrid, Electrical and Computer Engineering Department, Colorado State University, Fort Collins, Co 80525, Lawrence Livermore National Lab. (United States), Physics Department, Colorado State University, Fort Collins, Co 80525, JILA, Department of Physics, University of Colorado Boulder, Los Alamos National Laboratory, University of Alabama, University of Wyoming, University of Guelph, University of Guelph, Canadian Light source

  • Colin Roberts

    High Precision Devices, Boulder, CO, Raytheon, Tucson, AZ, Seagate Technology, Minneapolis, MN, Ball Aerospace (retired), Bloomfield, CO, New Mexico State University, Brigham Young University, Colorado State University, Heinrich-Heine-Universitat Dusseldorf, National Security Technologies, Universidad de Buenos Aires, Colorado State Univ, Colorado College, Utah State University, Advisor, Material Physics Group, Utah State University, Box Elder Innovations, LLC, JILA and Department of Physics, CU Boulder, JILA and Department of Mathematics, CU Boulder, Colorado State University, Fort Collins, Colorado 80523, USA, JILA, NIST and the University of Colorado, Boulder, NIST, University of Colorado / NIST, University of Colorado/JILA, Colorado Sch of Mines, Colorado School of Mines, Southwestern Indian Polytechnic Institute, UC-Berkeley, Colorado State University, Fort Collins, CO, Wroclaw University of Science and Technology, Wroclaw, Poland, JILA, University of Colorado and NIST, Harvard University and Harvard-MIT Center for Ultracold Atoms, Univ of Colorado - Boulder, USAFA, Univ of Denver, Boyce Research Initiatives and Educational Foundation, Brilliant Sky Observatory, San Diego Mesa College, Utah Valley University, University of Colorado Boulder, Brigham Young Univ - Provo, Oak Ridge National Laboratory, University of Sherbrooke, NIST Boulder, Universidad Complutense de Madrid, Electrical and Computer Engineering Department, Colorado State University, Fort Collins, Co 80525, Lawrence Livermore National Lab. (United States), Physics Department, Colorado State University, Fort Collins, Co 80525, JILA, Department of Physics, University of Colorado Boulder, Los Alamos National Laboratory, University of Alabama, University of Wyoming, University of Guelph, University of Guelph, Canadian Light source

  • Colin Roberts

    High Precision Devices, Boulder, CO, Raytheon, Tucson, AZ, Seagate Technology, Minneapolis, MN, Ball Aerospace (retired), Bloomfield, CO, New Mexico State University, Brigham Young University, Colorado State University, Heinrich-Heine-Universitat Dusseldorf, National Security Technologies, Universidad de Buenos Aires, Colorado State Univ, Colorado College, Utah State University, Advisor, Material Physics Group, Utah State University, Box Elder Innovations, LLC, JILA and Department of Physics, CU Boulder, JILA and Department of Mathematics, CU Boulder, Colorado State University, Fort Collins, Colorado 80523, USA, JILA, NIST and the University of Colorado, Boulder, NIST, University of Colorado / NIST, University of Colorado/JILA, Colorado Sch of Mines, Colorado School of Mines, Southwestern Indian Polytechnic Institute, UC-Berkeley, Colorado State University, Fort Collins, CO, Wroclaw University of Science and Technology, Wroclaw, Poland, JILA, University of Colorado and NIST, Harvard University and Harvard-MIT Center for Ultracold Atoms, Univ of Colorado - Boulder, USAFA, Univ of Denver, Boyce Research Initiatives and Educational Foundation, Brilliant Sky Observatory, San Diego Mesa College, Utah Valley University, University of Colorado Boulder, Brigham Young Univ - Provo, Oak Ridge National Laboratory, University of Sherbrooke, NIST Boulder, Universidad Complutense de Madrid, Electrical and Computer Engineering Department, Colorado State University, Fort Collins, Co 80525, Lawrence Livermore National Lab. (United States), Physics Department, Colorado State University, Fort Collins, Co 80525, JILA, Department of Physics, University of Colorado Boulder, Los Alamos National Laboratory, University of Alabama, University of Wyoming, University of Guelph, University of Guelph, Canadian Light source