Dr. Uwe Griebner
uwe.griebner(at)mbi-berlin.de
+49 30 6392 1457
C2: Solid State Light Sources
Haus C, 2.22

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 Publikationen
- Tm,Ho:KLu(Wo4)2 laser mode-locked near 2 µm by single single-walled carbon nanotubes Optics Express 22 (2014) 26872-26877
- Microchip laser operation of Tm,Ho:KLu(WO4)2 crystals Optics Express 22 (2014) 27976-27984
- Thermal lensing in Yb:KLu(WO4)2 crystals cut along the optical indicatrix axes Laser Physics Letters 11 (2014) 125802/1-6
- Diode-pumped continuous-wave (Ho,Tm):KLu(WO4)2 laser with >1 W output power Optical Materials Express 4 (2014) 2274-2279
- Generation of 40 ns laser pulses by a diode-pumped passively Q-switched Tm,Ho:YLF laser Laser Physics Letters 11 (2014) 115801/1-5
- Crystal growth, optical spectroscopy, and continuous-wave laser operation of Ho:KLu(WO4)2 crystals Applied Physics B 116 (2014) 455-466
- Thermal-lens-driven effects in Ng-cut Yb-and Tm-doped monoclinic KLu(WO4)2 crystals IEEE Journal of Quantum Electronics 50 (2014) 669-676
- Diode-pumped microchip Tm:KLu(WO4)2 laser with more than 3 W of output power Optics Letters 39 (2014) 4247-4250
- Characterization of the thermal lens in 3 at.% Tm:KLu(WO4)2 and microchip laser operation Laser Physics Letters 11 (2014) 075001/1-7
- 90-fs diode-pumped Yb:CLNGG laser mode-locked using single-walled carbon nanotube saturable absorber Optics Express 22 (2014) 5635-5640