MBI Staff Member – Personal info

Position

Project Coordinator 4.1: Implementation of Lasers and Measuring Techniques

Research

Development of advanced ultrashort pulse lasers, amplifiers, and parametric devices operating in the near- and mid-IR wavelength ranges including components and complete systems for direct implementation within other projects at MBI.

An example is the development of novel CPA laser sources emitting around 2 µm wavelength. This laser system operating at kilohertz repetition rate will serve as driver for OPCPA in the mid-IR. Figure (a) shows the simulated bifurcation diagram of a Ho:YLF regenerative amplifier (RA) at a 1 kHz repetition rate and 24 round trips indicating the most interesting operation regimes, i.e., stable double-pulsing (yellow coded bar) and the single-energy regime (green coded bar) beyond the final bifurcation point (BP final). Based on our model the RA is designed for operation in the single-energy regime beyond BPfinal. The measured complete RA bifurcation diagram of the re-designed RA at 1 kHz and 24 round trips is presented in Fig. (b). It agrees well with our numerical simulations [Fig. (a)]. Only the predicted multi-pulsing between 20 and 30 W pump power is less pronounced in the experiment. The highest pulse energy of 12 mJ can be extracted in the stable double-pulsing regime in the upper bifurcation branch (yellow coded bar), however at 0.5 kHz, the half of the repetition rate. BPfinal appears at a pump power of 47 W and denotes the transition to the single-energy regime where any multi-stabilities and chaotic behavior have been overcome. The extracted RA pulse energy of 9.7 mJ is the by far highest reported for 2-µm RAs operating in the single-energy regime. Taking into account the applied pump power of 50 W, the extraction efficiency is as high as 19.5%. Performing the transition from the stable double-pulsing to the single-energy regime, the RA’s pulse-to-pulse stability is further improved with a rms value <0.5%. Figure (c) shows the corresponding pulse stability measurement in the vicinity of BPfinal and beyond in the single-energy regime (green coded bar).

Curriculum vitae

since 1992 Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Berlin, Germany, staff scientist and project coordinator.

1993 - 1996 Ph.D. thesis at the Optical Institute, Technical University Berlin, Germany, with Prof. Horst Weber,
Title of thesis: Fiber bundle lasers with high average power,

1989 - 1992 Institute of Nonlinear Optics and Short Pulse Spectroscopy, Berlin, Germany, staff scientist,

1986 - 1989 Institute of Mechanics, Chemnitz, Germany, staff scientist,

1981 - 1986 Diploma degree in Physics; Physics Department, University of Jena, Germany,
Title of thesis: Characterization of lattice distorsions in LiF crystals,

MBI Publications

  1. Passively Q-switched Nd:glass fibre-bundle laser

    U. Griebner, R. Koch

    Electron. Lett. 31 (1995) 205-206
  2. Segmented solid-state laser resonators with graded reflectance micro-mirror analysis

    R. Grunwald, U. Griebner

    Pure Appl. Opt. 3 (1994) 435-440
  3. High-average-power flashlamp-pumped Nd:Glass fiber-bundle laser

    R. Koch, U. Griebner, R. Grunwald

    Applied Physics B 58 (1994) 403-407