Beam shaping of focused radiation of multimode lasers
2018 (English)In: High-Power Laser Materials Processing: Applications, Diagnostics, and Systems VII 2018 / [ed] Kaierle S.,Heinemann S.W., SPIE - International Society for Optical Engineering, 2018, Vol. 10525, article id 1052507Conference paper, Published paper (Refereed)
Abstract [en]
Performance of various laser technologies like welding, metal sheet cutting based on the use of powerful multimode fiber lasers, fiber-coupled solid-state and diode lasers can be improved by manipulation of energy distribution perpendicular and along optical axis. Welding, cladding with 0.5-2 mm size working spots benefit from "inverse-Gauss" intensity profiles, and doubled or tripled spots perpendicular to axis are good solutions to provide more uniform temperature profiles on a workpiece. Thick metal sheet cutting, some types of welding get benefits from distributing the laser energy along the optical axis resulting in more efficient usage of laser energy, higher and more stable cutting edge quality, faster processing. Since the radiation of multimode lasers is of low spatial coherence, characterized by big Beam Parameter Products (BPP) or M2 values, it is difficult to control the intensity distribution by methods other than imaging of a fiber end using a collimator and focusing objective. A promising suggested solution is combining of imaging the fiber end and geometrical separation of focused spots either perpendicular to or along the optical axis using dedicated optical components. Thus, energy of high power lasers is distributed among multiple foci. To provide reliable operation with multi-kW lasers and avoid damages the multi-focus optical devices are designed as refractive elements with smooth optical surfaces. The paper presents descriptions of multi-focus optics as well as examples of intensity profile measurements of beam caustics and application results
Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2018. Vol. 10525, article id 1052507
Series
Proceedings of SPIE--the International Society for Optical Engineering, ISSN 0277-786X, E-ISSN 1996-756X ; 10525
Keywords [en]
multi-focus, beam shaping, high power laser, multimode laser, welding, sheet metal cutting, cladding
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
URN: urn:nbn:se:ltu:diva-69306DOI: 10.1117/12.2287980ISI: 000449776000006Scopus ID: 2-s2.0-85047847165ISBN: 978-1-5106-1536-6 (print)OAI: oai:DiVA.org:ltu-69306DiVA, id: diva2:1216187
Conference
SPIE LASE, San Francisco, United States, 31 January - 1 February 2018
2018-06-112018-06-112019-09-13Bibliographically approved