MBI Research Fellow
Personal info


E-mail address:



Dr. Mark Mero


+49 30 6392 1271

Postdoctoral Researcher: Department A3

Member of Projects: 1.2 "Ultrafast Laser Physics and Nonlinear Optics," 2.3 "Time-resolved XUV science"


Research Topic

Short introduction:

Within this project, a dual-beam 100 kHz OPCPA system has been developed delivering an unprecedented average power at 1.55 μm in 430 μJ, 51 fs, passively CEP-stabilized pulses together with optically synchronized, 125 μJ, 73 fs pulses at 3.1 μm. In contrast to existing few-cycle mid-infrared (i.e., MIR, > 3µm), high repetition rate (i.e., >> 10 kHz) OPCPA systems operating at pulse energies above 100 µJ, our system is based on noncollinear KTA booster amplifiers seeded in the near-infrared at 1.55 µm, and a simple angular dispersion compensation technique [1]. Despite the noncollinear amplifying geometry, KTA can be efficiently used for generating broadband, high-quality MIR pulses at high average power. The resulting OPCPA system is the first ultrafast 100 kHz table-top source delivering two, simultaneously available, optically synchronized infrared beams (i.e., >= 1.5 µm) with average powers well above 10 W in each beam and a total average power exceeding 55 W after chirp compensation. Experiments utilizing a reaction microscope have already been started.

Further details on the large-scale system at MBI: Opt. Lett. 43(21), 5246 (2018).


Scheme of the dual-beam, 100 kHz OPCPA system. SHG, second-harmonic generation; WLC, white-light continuum generation; DFG, difference-frequency generation; OPA, optical parametric amplifier; PPLN, periodically poled LiNbO3; KTA, KTiOAsO4; CM, chirped mirrors; ADC, angular dispersion compensation; Si, silicon window.

Further development will include an upgrade of the 2-branch Yb-fiber pump/seed laser, the implementation of active CEP stabilization, and nonlinear pulse compression of the 1.55 μm beam. The 1.55 μm output of this unique system will serve as the pump of a high-flux soft-X-ray source with a spectrum reaching the water window, while the 3.1 μm beam will provide optically synchronized driver pulses for strong-field interactions.

The angular dispersion compensation scheme was first implemented on a small-scale system at the SALSA Photonics Lab at the Humboldt University of Berlin. The infrared optical parametric amplifier (OPA) part of the SALSA system is driven by only 40 μJ pulses at 1.03 μm (i.e., this is the pulse energy measured right at the output of the pump laser) and delivers 7.8 μJ, 38 fs, 1.53 μm and 2.3 μJ, 53 fs, CEP-stable, 3.1 μm pulses at a repetition rate of 100 kHz. One of the remarkable features of this system is the angular-dispersion-compensated 3.1 µm idler beam. Through careful beam and pulse characterization, and high-harmonic generation in YAG (odd orders up to the 9th without much effort), we proved that the corrected idler beam is diffraction-limited, astigmatism-free, and compressible to its transform-limited pulse duration corresponding to only 5 optical cycles. By a direct comparison to our previous SALSA OPA source based entirely on PPLN, we also showed that the performance of a noncollinear, KTA-based power amplifier for dual-beam operation at a given broad gain bandwidth is superior to the performance of a collinear, PPLN-based booster stage in terms of conversion efficiency, beam quality, and carrier-envelope phase (CEP) noise. Successful implementation of this simple angular dispersion compensation scheme on the large-scale system at MBI proves its scalability to high average powers.

[1] Z. Heiner, V. Petrov, G. Steinmeyer, M. J. J. Vrakking, and M. Mero, “100-kHz, dual-beam OPA delivering high-quality, 5-cycle angular-dispersion-compensated mid-infrared idler pulses at 3.1 μm,” Opt. Express 26(20), 25793 (2018). [link]

The OPA source at SALSA is part of the first 100 kHz broadband vibrational sum-frequency generation (BB-VSFG) spectrometer [2]. The early version of the OPA source was based on PPLN amplifier stages and was used to investigate average-power-induced thermal effects in BB-VSFG experiments conducted on molecular layers at an interface between two transparent phases. The paper summarizing the results was Editor's Pick at the Journal of Chemical Physics [3].

[2] Z. Heiner, V. Petrov, and M. Mero, "Compact, high-repetition-rate source for broadband sum-frequency generation spectroscopy," APL Photonics 2(6), 066102 (2017). [link]

[3] F. Yesudas, M. Mero, J. Kneipp, and Z. Heiner, "Vibrational sum-frequency generation spectroscopy of lipid bilayers at repetition rates up to 100 kHz," J. Chem. Phys. 148(10), 104702 (2018). [link]

Curriculum vitae

  • 07/2012 - present: Postdoctoral Researcher, Max Born Institute
  • 04/2012-07/2012: Postdoctoral visit, Department of Chemistry, University of Delaware, Newark, DE, U.S.A.
  • 06/2008 - 12/2011: Postdoctoral Researcher, Department of Optics and Quantum Electronics, University of Szeged, Szeged, Hungary
  • 04/2010 - 07/2010: Postdoctoral visit, Max Planck Insitute for Quantum Optics, Garching, Germany
  • 01/2010 - 03/2010: Postdoctoral visit, Department of Physics and Astronomy, Albuquerque, NM, U.S.A.
  • 11/2007 - 04/2008: Postdoctoral visit, Department of Physics and Astronomy, Albuquerque, NM, U.S.A.
  • 05/2006 - 10/2007: Postdoctoral Researcher, Max Born Institute
  • 01/2006 - 03/2006: Temporary Research Position, CVI Laser LLC, NM, U.S.A.
  • Dec. 2005: Ph.D. in Optical Science and Engineering, Department of Physics and Astronomy, Albuquerque, NM, U.S.A.
  • 1998: Diploma in Physics, University of Szeged, Szeged, Hungary


Research Highlights


Publications at MBI

Citations on Google Scholar

List of own publications with no relation to MBI:

  • Compression methods for XUV attosecond pulses
    M. Mero, F. Frassetto, P. Villoresi, L. Poletto, K. Varju
    Opt. Express 19, 23420 (2011)
  • Protein-based ultrafast photonic switching
    L. Fabian, Z. Heiner, M. Mero, M. Kiss, E. K.Wolff, P. Ormos, K. Osvay, A. Der
    Opt. Express 19, 18861 (2011)
  • Subpicosecond all-optical switching by the protein bacteriorhodopsin
    L. Fabian, Z. Heiner, M. Mero, M. Kiss, E. K.Wolff, P. Ormos, K. Osvay, A. Der
    European Biophysics Journal with Biophysics Letters 40, Suppl. 1, 236 (2011)
  • Generation of energetic femtosecond green pulses based on an OPCPA-SFG scheme
    M. Mero, A. Sipos, G. Kurdi, K. Osvay
    Opt. Express 19, 9646 (2011)
  • Subpicosecond Photonic Switching Based on Bacteriorhodopsin
    P. Ormos, L. Fabian, Z. Heiner, M. Mero, M. Kiss, E. K. Wolff, K. Osvay, A. Der
    Biophysical Journal 100, Suppl. 1, 485 (2011)
  • Modeling the effect of native and laser-induced states on the dielectric breakdown of wide band gap optical materials by multiple subpicosecond laser pulses
    L.A. Emmert, M. Mero, W. Rudolph
    J. Appl. Phys. 108, 043523 (2010)
  • TixSi1-xO2 optical coatings with tunable index and their response to intense subpicosecond laser pulse irradiation
    D. Nguyen, L. A. Emmert, I. V. Cravetchi, M. Mero, W. Rudolph, M. Jupe, M. Lappschies, K. Starke, D. Ristau
    Appl. Phys. Lett. 93, 261903 (2008)
  • Femtosecond dynamics of dielectric films in the pre-ablation regime
    M. Mero, A. J. Sabbah, J. Zeller, W. Rudolph
    Appl. Physics A 81, 317 (2005)
  • On the damage behavior of dielectric films when illuminated with multiple femtosecond laser pulses
    M. Mero, B. Clapp, J. C. Jasapara, W. Rudolph, D. Ristau, K. Starke, J. Krüger, S. Martin, W. Kautek
    Opt. Eng. 44, 051107 (2005)
  • Scaling laws of femtosecond laser pulse induced breakdown in oxide films
    M. Mero, J. Liu, W. Rudolph, D. Ristau, K. Starke
    Phys. Rev. B 71, 115109 (2005)
  • Retrieval of the dielectric function of thin films from femtosecond pump-probe experiments
    J. Jasapara, M. Mero, W. Rudolph
    Appl. Phys. Lett. 80, 2637 (2002)
  • Unbalanced third-order correlations for full characterization of femtosecond pulses
    J. W. Nicholson, M. Mero, J. Jasapara, W. Rudolph
    Opt. Lett. 25, 1801 (2000)