1983:

MBI staff member
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Ingo Will

will@mbi-berlin.de

+49 30 6392 1320

Scientist

Project Coordinator: 4.1

Member of Projects: 4.1, 1.1

 

Research Topic


Short introduction:


My research mainly deals with the development of solid-state lasers and optical-parametric amplifiers.

  1. Diode-pumped laser of high average power, in particular:
    • lasers amplifiers utilizing Thin-disks (laser material Yb:YAG)
    • fiber lasers and fiber amplifiers based on Photonic Crystal fibers
    • Femtosecond Yb:KGW oscillators and amplifiiers
  2. OCPA systems pumped with Thin-disk lasers for generating femtosecond pulses

The second focus of my work consists in the development of photoinjector drive lasers. When focusing these pulses onto a photocathode, electron bunches of high density are generated. After being accelerated in a linac, these bunches are well suited for driving Free Electron Lasers (FELs). The properties of these electron bunches can be optimized by appropriately tuning the shape of the picosecond laser pulses. To accomplish this, we have developed the first Yb:YAG laser in the world, that can generate trains (bursts) of ultraviolet laser pulses with variable shape.
Several of these lasers are used at electron accelerators and FELs, such as:

  1. Lasers for driving the photo injectors:
    • Photoinjector drive lasers for the superconducting photo injector at the HZDR (Dresden Rossendorf),
    • Laser for development and test of photoinjectors at the HZB Berlin
  2. Burst-mode lasers for driving the photo injectors of superconducting linacs that are operated with bursts of electron bunches:
    • Photoinjector drive laser for the European XFEL at DESY Hamburg
    • Photocathoce lasers for the FLASH FEL and, previously, the TESLA Test Facility (TTF)) and the at DESY Hamburg
    • Photocathode lasers with shaped pulses, e.g. for the Photoinjektor Test Facility Zeuthen (PITZ). This outstanding laser generates trains of flat top pulses with sharp edges (< 2 ps). Since 2008, this laser has been applied for driving the Photo injectors at PITZ. A significant improvement of the emittance of the generated electron beams was achieved by optimizing the shape of the laser pulses.

Pulse trains messured in the XFEL photokathode laser after the oscillator, the fiber amplifiier , the multipass ampliifer and the booster

Curriculum vitae


1994 - today: Scientist and Project Manager of several projects at the MBI as well as projects conducted in cooperation with DESY, HZB Berlin and HZDR Dresden (Rossendorf) to develop special solid-state lasers and femtosecond OPCPA systems
1993 - 1994: Scientist and project manager at the Max-Born-Institute (MBI) Berlin
Field of work:
  • Development of CPA Solid-state laser systems,
  • Laser plasma interaction,
  • Diagnostics of laser-induced plasmas.
1992-1993:

Postdoctoral appointee at the Laboratory for Laser Energetics, Rochester, (USA).
Working areas:

  • Highly-stable diode-pumped Nd:YLF amplifiers
  • Development of a Large Aperture Ring Amplifier (LARA) for large flashlamp-pumped Nd:glass fusion laser systems.
1991 - 1992: Scientist at the Institute for Nonlinear Optics and Short-pulse spectroscopy Berlin (Germany).
Working areas:
  • Pulsed solid-state lasers,
  • Laser plasma interaction.
1991:

PhD from the Technical University Berlin on pulse amplification in high-power solid-state laser systems, with Prof. H. Weber and Prof. W. Brunner

1985 - 1991:

Scientist at the Central Institute for Optics and Spectroscopy Berlin.

1984 - 1985:

Military service in Rostock/Germany.

1985 - 1991:

Scientist at the Central Institute for Optics and Spectroscopy Berlin.

1983:

Diploma at Humboldt University Berlin

1978 - 1983:

Study of physics at the Warshaw University (Poland)
and at the Humbold University Berlin (Germany)

 

Research Highlights

 

Flat-top UV pulses for PITZ, FLASH and the upcoming XFEL at DESY Hamburg

We have recently developed a photoinjector drive laser generating trains (bursts) of UV pulses of programmable shape, in particular of flat-top pulses with sharp rising and falling edges. It is expected, that the emittance of the generated electron beam can be significantly improved by appropriately shaping the laser pulses.
The present laser developed at the MBI for the PITZ installation at DESY Zeuthen allows for a large variety of the shape of the generated pulses. The figure below shows some of them:

Figure: Different shapes of the UV pulses produced with the Yb:YAG laser system

The laser system generating the desired trains of shaped picosecond UV pulses consists of the following components:

  • A femtosecond Yb:KGW laser oscillator, that is precisely synchronized to the RF master oscillator of the linear accelerator,

  • he pulse shaper,
  • chain of Yb:YAG amplifiers,
  • wavelength converter that converts the infrared laser pulses of the laser to the ultraviolet (4-th harmonics),
  • so-called optical sampling system for measuring the pulse shape by cross correlation,
  • computerized control system that allows for full remote control of the laser.

The actual shaping of the pulses is accomplished by a multicrystal birefringent filter located before the entrance of the amplifier chain of the laser system. The pulse shaping process can be explained by a coherent staking of 14 replicas of the short input pulse. In order to control the mutual phase of these replicas precisely, the temperatures of the 13 birefringent crystals of the shaper are tuned with 0.01° C accuracy.

The described laser developed at the MBI is used since summer 2008 for driving the photo injector of the PITZ installation at DESY Zeuthen. During 2009, the laser was further improved. In particular, the number of generated pulse shapes was increased.
We expect that with an optimized pulse shape the emittance of the electron beam will be reduced to a value below 1 pi mm mrad in summer 2010. This low emittance is required for the electron beams of the upcoming XFEL at DESY in Hamburg. To reach that emittance, DESY is presently building a new RF photo injector and an improved RF system.

Figure: Shape of the produced flat-top picosecond pulses with sharp edges

Publications


Publications at MBI