Transverse intensity transformation by laser amplifiers

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

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

Abstract

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
PublisherSPIE
Number of pages6
DOIs
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
PublisherSPIE-INT SOC OPTICAL ENGINEERING
Volume9343
ISSN (Print)0277-786X

Conference

ConferenceConference on Laser Resonators, Microresonators, and Beam Control XVII
CountryCanada
Period9/02/1512/02/15

Keywords

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

Cite this

Litvin, I. A., King, G., Collett, O. J. P., & Strauss, H. J. (2015). Transverse intensity transformation by laser amplifiers. In AV. Kudryashov, AH. Paxton, VS. Ilchenko, L. Aschke, & K. Washio (Eds.), Laser Resonators, Microresonators, and Beam Control XVII (Proceedings of SPIE; Vol. 9343). SPIE. https://doi.org/10.1117/12.2077586