Novel hollow fiber compressor for high power, multi-mJ ultrafast lasers

T. Nagy, P. Simon, W. Schweinberger, A. Sommer, M. Schultze, R. Kienberger, F. Krausz

Research output: Chapter in Book/Report/Conference proceedingConference paperpeer-review


en] Complete text of publication follows. The current trends in ultrafast laser development include, besides the reduction of the pulse duration, also the up-scaling of the pulse energy and the increase of the repetition rate. Recently, multi-mJ, multi-kHz lasers delivering sub-30 fs pulses have become available. The compression of the output pulses of such lasers to sub-5 fs duration is a challenging task. In order to maintain good temporal contrast and beam profile, the preferred way for spectral broadening is to use noble-gas-filled hollow fibers. For launching multi-mJ pulses in the waveguide, its inner diameter has to be large in order to keep the intensity at low levels so that the ionization losses are still tolerable. For optimal in-coupling the differential pressure scheme is very favourable, which, however requires longer waveguide lengths to compensate for the reduced effective interaction length caused by the pressure gradient. Recently, a novel hollow fiber construction has been developed comprising a waveguide formed by a stretched flexible capillary tube. This special construction resolves the usual strong limitation of the length of the waveguide, provides excellent straightness, and inherently supports the differential pressure scheme. The only drawback of the flexible fiber unit to date was its susceptibility to thermal damage in case of high average power input beams. To solve this problem we present a novel composite fiber unit, which consists of a thick-walled taper followed by a long flexible fiber. This construction combines the advantages of both types: the high resistibility of the taper and the free length-scalability of a flexible fiber. In order to demonstrate the potential of the new fiber design, a 2 m long composite fiber with an inner diameter of 320 μm was placed at the output of a CPA Ti:Sa laser system comprising an oscillator, a grating-prism (grism) stretcher, two multi-pass amplifier stages and a compressor combining bulk glass blocks with chirped mirrors. The laser delivers 26 fs pulses with a pulse energy of 2 mJ at a repetition rate of 4 kHz. The whole system can be CEP stabilized and the spectral amplitude and phase can be fully controlled by a programmable AOM which is implemented in the first multi-pass amplifier. Using a pressure gradient scheme with 1.7 bar Ne, a spectrum with ∼ 500 nm bandwidth has been recorded (shown in the Figure) at an overall transmission of higher than 50%.
Original languageEnglish
Title of host publication31. European Conference on Laser Interaction with Matter. Book of abstracts
Place of PublicationWien
Publication statusPublished - Jul 2010
Externally publishedYes
Event 31. European Conference on Laser Interaction with Matter - Budapest, Budapest, Hungary
Duration: 6 Sept 201010 Sept 2010


Conference 31. European Conference on Laser Interaction with Matter


  • Energy transfer
  • Fused silica
  • Phase shift
  • Pump probe spectroscopy
  • Refractive index
  • Ultrashort pulses

Fields of Expertise

  • Advanced Materials Science


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