Compact high-repetition-rate source of coherent 100 eV radiation

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Coherently enhancing laser pulses in a passive cavity provides ideal conditions for high-order harmonic generation in a gas, with repetition rates around 100 MHz (refs 1,2,3). Recently, extreme-ultraviolet radiation with photon energies of up to 30 eV was obtained, which is sufficiently bright for direct frequency-comb spectroscopy at 20 eV (ref. 4). Here, we identify a route to scaling these radiation sources to higher photon energies. We demonstrate that the ionization-limited attainable intracavity peak intensity increases with decreasing pulse duration. By enhancing nonlinearly compressed pulses of an Yb-based laser and coupling out the harmonics through a pierced cavity mirror, we generate spatially coherent 108 eV (11.45 nm) radiation at 78 MHz. Exploiting the full potential of the demonstrated techniques will afford high-photon-flux ultrashort-pulsed extreme-ultraviolet sources for a number of applications in science and technology, including photoelectron spectroscopy, coincidence spectroscopy with femtosecond to attosecond resolution5,6 and characterization of components and materials for nanolithography7.

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Figure 1: Experimental set-up for intracavity HHG.
Figure 2: XUV output coupling mirror, fundamental beam profiles and calculated output coupling efficiency.
Figure 3: Intensity upper bound for uncompressed and nonlinearly compressed pulses.
Figure 4: Harmonic spectra and beam profiles.


  1. 1

    Gohle, C. et al. A frequency comb in the extreme ultraviolet. Nature 436, 234–237 (2005).

  2. 2

    Jones, R. J., Moll, K. D., Thorpe, M. J. & Ye, J. Coherent frequency combs in the vacuum ultraviolet via high-harmonic generation inside a femtosecond enhancement cavity. Phys. Rev. Lett. 94, 193201 (2005).

  3. 3

    Hartl, I. et al. Cavity-enhanced similariton Yb-fiber laser frequency comb: 3×1014 W/cm2 peak intensity at 136 MHz. Opt. Lett. 32, 2870–2872 (2007).

  4. 4

    Cingöz, A. et al. Direct frequency comb spectroscopy in the extreme ultraviolet. Nature 482, 68–71 (2012).

  5. 5

    Stolow, A., Bragg, A. E. & Neumark, D. M. Femtosecond time-resolved photo electron spectroscopy. Chem. Rev. 104, 1719–1757 (2004).

  6. 6

    Zhang, C-H. & Thumm, U. Attosecond photoelectron spectroscopy of metal surfaces. Phys. Rev. Lett. 102, 123601 (2009).

  7. 7

    Lin, J. et al. At-wavelength inspection of sub-40 nm defects in extreme ultraviolet lithography mask blank by photoemission electron microscopy. Opt. Lett. 32, 1875–1877 (2007).

  8. 8

    Krausz, F. & Ivanov, M. Attosecond physics. Rev. Mod. Phys. 81, 163–234 (2009).

  9. 9

    Hentschel M. et al. Attosecond metrology. Nature 414, 509–513 (2001).

  10. 10

    Sansone, G., Poletto, L. & Nisoli, M. High-energy attosecond light sources. Nature Photon. 5, 655–663 (2011).

  11. 11

    Mills, A., Hammond, T. J., Lam, M. H. C. & Jones, D. J. XUV frequency combs via femtosecond enhancement cavities. J. Phys. B 45, 142001 (2012).

  12. 12

    Park, I-Y. et al. Plasmonic generation of ultrashort extreme-ultraviolet light pulses. Nature 5, 677–681 (2011).

  13. 13

    Vernaleken, A. et al. Single-pass high-harmonic generation at 20.8 MHz repetition rate. Opt. Lett. 36, 3428–3430 (2011).

  14. 14

    Stockman, M., Kling, M. F., Kleineberg, U. & Krausz, F. Attosecond nanoplasmonic-field microscope. Nature Photon. 1, 539–544 (2007).

  15. 15

    Chew, S. H. et al. Time-of-flight-photoelectron emission microscopy on plasmonic structures using attosecond extreme ultraviolet pulses. Appl. Phys. Lett. 100, 051904 (2012).

  16. 16

    Sansone, G. et al. Electron localization following attosecond molecular photoionization. Nature 465, 763–766 (2010).

  17. 17

    Bergues, B. et al. Attosecond tracing of correlated electron-emission in non-sequential double ionization. Nat. Commun. 3, 813 (2012).

  18. 18

    Yost, D. et al. Power optimization of XUV frequency combs for spectroscopy applications [Invited]. Opt. Express 19, 23483–23493 (2011).

  19. 19

    Lee, J., Carlson, D. R. & Jones, R. J. Optimizing intracavity high harmonic generation for XUV fs frequency combs. Opt. Express 19, 23315–23326 (2011).

  20. 20

    Carlson, D. R., Lee, J., Mongelli, J., Wright, E. M. & Jones, R. J. Intracavity ionization and pulse formation in femtosecond enhancement cavities. Opt. Lett. 36, 2991–2993 (2011).

  21. 21

    Allison, T. K., Cingöz, A., Yost, D. C. & Ye, J. Extreme nonlinear optics in a femtosecond enhancement cavity. Phys. Rev. Lett. 107, 183903 (2011).

  22. 22

    Moll, K. D., Jones, R. J. & Ye, J. Output coupling methods for cavity based high-harmonic generation. Opt. Express 14, 8189–8197 (2006).

  23. 23

    Eidam, T., Röser, F., Schmidt, O., Limpert, J. & Tünnermann, A. 57 W, 27 fs pulses from a fiber laser system using nonlinear compression. Appl. Phys. B 92, 9–12 (2008).

  24. 24

    Pupeza, I. et al. Power scaling of a high-repetition-rate enhancement cavity. Opt. Lett. 35, 2052–2054 (2010).

  25. 25

    Jocher, C., Eidam, T., Hädrich, S., Limpert, J. & Tünnermann, A. Sub 25 fs pulses from solid core nonlinear compression stage at 250 W of average power. Opt. Lett. 37, 4407–4410 (2012).

  26. 26

    Paschotta, R. Beam quality deterioration of lasers caused by intracavity beam distortions. Opt. Express 14, 6069–6074 (2006).

  27. 27

    Hädrich, S. et al. Generation of µW level plateau harmonics at high repetition rate. Opt. Express 19, 19374–19383 (2011).

  28. 28

    Jaegle, P. Coherent Sources of XUV Radiation (Springer, 2006).

  29. 29

    L'Huillier, A., Balcou, P., Candel S., Schafer, K. J. & Kulander, K. C. Calculations of high-order harmonic-generation processes in xenon at 1064 nm. Phys. Rev. A 46, 2778–2790 (1992).

  30. 30

    Drever, R. W. P. et al. Laser phase and frequency stabilization using an optical resonator. Appl. Phys. B 31, 97–105 (1983).

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This work was supported by the Deutsche Forschungsgemeinschaft (DFG) Cluster of Excellence, Munich Centre for Advanced Photonics (MAP) (, by the KORONA Max-Planck-Institut für Quantenoptik (MPQ)/Fraunhofer-Institut für Lasertechnik (ILT) cooperation and by the Bundesministerium für Bildung und Forschung (BMBF) under PhoNa − Photonische Nanomaterialien (contract no. 03IS2101B).

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The project was planned by I.P., S.H., J.R., J.L., T.U., A.T., T.W.H., A.A., F.K. and E.F. The Yb:fibre laser was designed and built by T.E., J.L. and A.T. The piercing in the substrate for the XUV output coupling mirror was realized by D.E., J.W. and P.R. The HHG experiments and model development were performed by I.P., S.H., T.E., H.C., J.W. and E.F. All authors discussed the results and contributed to the final manuscript.

Correspondence to I. Pupeza.

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Pupeza, I., Holzberger, S., Eidam, T. et al. Compact high-repetition-rate source of coherent 100 eV radiation. Nature Photon 7, 608–612 (2013) doi:10.1038/nphoton.2013.156

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