Transverse intensity transformation by laser amplifiers

Igor A. Litvin*, Gary King, Oliver J. P. Collett, Hencharl J. Strauss

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Lasers beams with a specific intensity profile such as super-Gaussian, Airy or Dougnut-like are desirable in many applications such as laser materials processing, medicine and communications. We propose a new technique for laser beam shaping by amplifying a beam in an end-pumped bulk amplifier that is pumped with a beam that has a modified intensity profile. Advantages of this method are that it is relatively easy to implement, has the ability to reshape multimode beams and is naturally suited to high power/energy beams. Both three and four level gain materials can be used as amplifier media. However, a big advantage of using three level materials is their ability to attenuate of the seed beam, which enhances the contrast of the shaping.

We first developed a numerical method to obtain the required pump intensity for an arbitrary beam transformation. This method was subsequently experimentally verified using a three level system. The output of a 2.07 mu m seed laser was amplified in a Ho: YLF bulk amplifier which was being pumped by a 1.89 mu m Tm:YLF laser which had roughly a TEM10 Hermit Gaussian intensity profile. The seed beam was amplified from 0.3 W to 0.55 W at the full pump power of 35 W. More importantly, the beam profile in one transverse direction was significantly shaped from Gaussian to roughly flat-top, as the model predicted. The concept has therefore been shown to be viable and can be used to optimise the beam profile for a wide range of applications.

Original languageEnglish
Title of host publicationLaser Resonators, Microresonators, and Beam Control XVII
EditorsAV Kudryashov, AH Paxton, VS Ilchenko, L Aschke, K Washio
Place of PublicationBellingham
Number of pages6
Publication statusPublished - 2015
EventConference on Laser Resonators, Microresonators, and Beam Control XVII - San Francisco, Canada
Duration: 9 Feb 201512 Feb 2015

Publication series

NameProceedings of SPIE
ISSN (Print)0277-786X


ConferenceConference on Laser Resonators, Microresonators, and Beam Control XVII


  • Beam shaping
  • laser
  • oscillator
  • amplifier
  • MOPA
  • mid-infrared
  • solid-state
  • Ho: YLF
  • Holmium
  • Thulium
  • end-pumped


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