MBI Staff Member – Personal info


Staff Scientist

Member of Projects:

1.2 Ultrafast Laser Physics and Nonlinear Optics

2.1 Time-resolved XUV-science

2.2 Strong-field Few-body Physics


This project is devoted to the research and development of ultrafast infrared driver sources for atomic and molecular attosecond strong-field spectroscopy and ultrafast electron diffraction experiments.

Curriculum vitae

07/2012 - present: Max Born Institute

04/2012-07/2012: Dept. of Chemistry, University of Delaware, Newark, DE, U.S.A.

06/2008 - 12/2011: Dept. 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, Dept. of Physics and Astronomy, Albuquerque, NM, U.S.A.

11/2007 - 04/2008: Postdoctoral visit, Dept. of Physics and Astronomy, Albuquerque, NM, U.S.A.

05/2006 - 10/2007: Max Born Institute

01/2006 - 03/2006: Temporary Research Position, CVI Laser LLC, NM, U.S.A.

2005: Ph.D. in Optical Science and Engineering, Dept. of Physics and Astronomy, Albuquerque, NM, U.S.A.

1998: Diploma in Physics, Univ. of Szeged, Szeged, Hungary

Recent highlight(s)


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 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.

[1] M. Mero, Z. Heiner, V. Petrov, H. Rottke, F. Branchi, G. M. Thomas, M. J. J. Vrakking, "43 W, 1.55 μm and 12.5 W, 3.1 μm dual-beam, sub-10 cycle, 100 kHz optical parametric chirped pulse amplifier," Opt. Lett. 43, 5246 (2018). [link]


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 [2]. 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 [3], 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.

The OPA source at SALSA is part of the first 100 kHz broadband vibrational sum-frequency generation (BB-VSFG) spectrometer [3]. 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 [4]. Recently, the spectrometer was successfully used to characterize single- and two-component lipid monolayers as a function of surface pressure and mixture ratio [5].

At a pump wavelength of 1 µm, extension of the wavelength range to the MIR range above 5 µm can be achieved by employing novel wide-gap non-oxide crystals. We implemented a small-scale OPA based on LiGaS2 which was integrated into a BB-VSFG spectrometer. By doing this, we demonstrated (i) the first sub-100 fs, µJ scale pulses in the 7-9 µm range from an LGS OPA pumped at 1 µm, and (ii) the first 100 kHz BB-VSFG measurements in the fingerprint region [6].

[2] 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, 25793 (2018). [link]

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

[4] 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, 104702 (2018). [link]

[5] F. Yesudas, M. Mero, J. Kneipp, and Z. Heiner, "High-resolution and high-repetition-rate vibrational sum-frequency generation spectroscopy of one-and two-component phosphatidylcholine monolayers," Anal. Bioanal. Chem. (2019). [link]

[6] Z. Heiner, L. Wang, V. Petrov, and M. Mero, "Broadband vibrational sum-frequency generation spectrometer at 100 kHz in the 950-1750 cm−1 spectral range utilizing a LiGaS2 optical parametric amplifier," submitted to Optics Express (2019), arXiv:1904.00046 [link]


Leibniz-Gemeinschaft (SAW-2012-MBI-2); Horizon 2020 Framework Programme (H2020) (654148)

MBI Publications

  1. Sub-100-fs bulk solid-state lasers near 2-micron

    V. Petrov, Y. Wang, W. Chen, Z. Pan, Y. Zhao, L. Wang, M. Mero, S. Y. Choi, F. Rotermund, W. B. Cho, W. Jing, H. Huang, H. Yuan, H. Cai, L. Zhang, Z. Lin, P. Loiko, X. Mateos, X. Xu, J. Xu, H. Yu, H. Zhang, S. Suomalainen, M. Guina, A. Härkönen, U. Griebner

    SPIE Proceedings, Eleventh International Conference on Information Optics and Photonics (CIOP1019), Xi'an, China 11209 (2019) 112094G/1-16
  2. 43  W, 1.55  μm and 12.5  W, 3.1  μm dual-beam, sub-10 cycle, 100  kHz optical parametric chirped pulse amplifier

    M. Mero, Z. Heiner, V. Petrov, H. Rottke, F. Branchi, G. M. Thomas, M. J. J. Vrakking

    Optics Letters 43 (2018) 5246-5249
  3. 100-kHz, dual-beam OPA delivering high-quality, 5-cycle angular-dispersion-compensated mid-infrared idler pulses at 3.1 μm

    Z. Heiner, V. Petrov, G. Steinmeyer, M. J. J. Vrakking, M. Mero

    Optics Express 26 (2018) 25793-25804
  4. 78  fs SWCNT-SA mode-locked Tm:CLNGG disordered garnet crystal laser at 2017 nm

    Y. Wang, Y. Zhao, Z. Pan, J. E. Bae, S. Y. Choi, F. Rotermund, P. Loiko, J. M. Serres, X. Mateos, H. Yu, H. Zhang, M. Mero, U. Griebner, V. Petrov

    Optics Letters 43 (2018) 4268-4271
  5. Hidden amplitude-phase correlations in the carrier-envelope noise of mode-locked lasers

    N. Raabe, T. Feng, M. Merö, H. Tian, Y. Song, W. Hänsel, R. Holzwarth, A. Sell, A. Zach, G. Steinmeyer

    SPIE Proceedings Series 10089 (2017) 1008907/1-7
  6. Sub-100  fs Tm:MgWO4 laser at 2017 nm mode locked by a graphene saturable absorber

    Y. Wang, W. Chen, M. Mero, L. Zhang, H. Lin, Z. Lin, G. Zhang, F. Rotermund, Y. J. Cho, P. Loiko, X. Mateos, U. Griebner, V. Petrov

    Optics Letters 42 (2017) 3076-3079
  7. Compact, high-repetition-rate source for broadband sum-frequency generation spectroscopy

    Z. Heiner, V. Petrov, M. Mero

    APL Photonics 2 (2017) 066102/1-8
  8. High-power, few-cycle, angular dispersion compensated mid-infrared pulses from a noncollinear optical parametric amplifier

    M. Mero, V. Petrov

    IEEE Photonics Journal 9 (2017) 3200408/1-8
  9. Numerical study of spatiotemporal distortions in noncollinear optical parametric chirped-pulse amplifiers

    A. Giree, M. Mero, G. Arisholm, M. J. J. Vrakking, F. J. Furch

    Optics Express 25 (2017) 3104-3121
  10. High repetition rate, femtosecond and picosecond laser induced damage thresholds of Rb:KTiOPO₄ at 1.03 μm

    F. Bach, M. Mero, V. Pasiskevicius, A. Zukauskas, V. Petrov

    Optical Materials Express 7 (2017) 744-750