Beam shaping diffractive optical elements for high power laser applications

Andrew J. Waddie, Adam J. Caley, Mohammad R. Taghizadeh, Keren K. Jobbins

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

Abstract

Diffractive Optical Elements (DOEs) are lightweight, thin optical components with many applications in laser beam-shaping. In this paper we consider the application of DOEs for coupling of high power Nd:YAG laser light to fibre For the laser system in question intra-cavity DOEs are considered for the generation of a super-Gaussian cavity mode, while an extra-cavity element is considered for shaping the beam to produce a profile suitable for fibre coupling. The arrangement to be considered in our application involves coupling a 100mJ, 20ns pulse laser beam of 5mm diameter into 3 fibres, each with a core diameter of 400µm, positioned in an equilateral triangle formation with a centre to centre spacing of 2mm. The threshold power density for the fibres is 4.5GW/cm2. 512x512 pixel DOEs with 16 phase levels have been optimized using the iterative Fourier transform algorithm (IFTA). The optimized element produces spots with a radius of 14 diffraction orders. The modeled efficiency of the element is 91.4% with a peak power of 1.26GW/cm2. Experimental measurements using a low power 633nm source equate to a peak power of 2.65GW/cm2 for the high power laser, well within the damage threshold.

Original languageEnglish
Title of host publicationOptical Technologies for Arming, Safing, Fuzing, and Firing IV
Volume7070
DOIs
Publication statusPublished - 2008
EventOptical Technologies for Arming, Safing, Fuzing, and Firing IV - San Diego, CA, United States
Duration: 13 Aug 200814 Aug 2008

Conference

ConferenceOptical Technologies for Arming, Safing, Fuzing, and Firing IV
CountryUnited States
CitySan Diego, CA
Period13/08/0814/08/08

Keywords

  • Beamshape
  • Diffractive optical element

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