Laser Cutting with annular intensity distribution

Pang, Hao; Haecker, Tobias

doi:10.1016/j.procir.2020.09.168

Cited by 18 publications

(3 citation statements)

References 9 publications

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“…The annulus width remains constant within the propagation distance and it is just related to the diameter of the input beam, the axicon cone angle, and the spacing between the two elements. Single axicons have been previously used in various applications like imaging with extended depth of field, 2 laser glass cutting, 3 or fluorescence microscopy, 4 among others. When combined with a second axicon element, double axicons can also be found in corneal surgery procedures 5 and optical trapping systems.…”

Section: Icso 2022 International Conference On Space Opticsmentioning

confidence: 99%

Double axicons to maximize Optical Feeder Links transmission on conventional telescopes

Martínez

Farley

Stadler

et al. 2023

International Conference on Space Optics — ICSO 2022

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In this paper we speak about the double-axicon unit built for the CaNaPy instrument, the LGS-AO backbone of the ESA ALASCA TRL6 facility, to demonstrate Optical Feeder Links for Satellite Communications in 2023 using Laser Guide Star Adaptive Optics technologies.The ALASCA system will co-propagate a guidestar laser (λ = 589 nm) and an infrared laser (λ = 1075 nm), using the monostatic approach through the entire 1-m Optical Ground Station (OGS) at Teide Observatory, Canary Islands (Spain). Provisions have been made to use either the full aperture or a section of the OGS primary mirror.The OGS telescope secondary mirror would introduce 30% central vignetting losses on the uplink laser beams. In order to minimise the losses, a double-axicon module shapes the gaussian beam as an annulus, thus optimises the laser profile to match the telescope pupil and nulls the losses, achieving the most efficient coupling to the OGS telescope.We present the CaNaPy axicon module design and analysis for the 589-nm laser as well as the ALASCA axicon module design for the OFL; we describe the tests done and the gain achieved in power transmission when shaping the laser compared to propagating a conventional Gaussian beam through a telescope with a non-negligible central obstruction.

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Section: Icso 2022 International Conference On Space Opticsmentioning

confidence: 99%

Double axicons to maximize Optical Feeder Links transmission on conventional telescopes

Martínez

Farley

Stadler

et al. 2023

International Conference on Space Optics — ICSO 2022

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“…Owing to mixing of wavefronts, the irradiance profile is rapidly transformed from uniform at the fiber end to parabolic or Gaussian-like after a few centimeters of propagation in free space. Control of the irradiance distribution of such beams using beam shaping techniques based on wavefront manipulation is very difficult and can be effectively implemented for relatively large laser spots 3,19 , usually a few millimetres or more. In the case of less than 2 mm diameter of a resulting spot, popular beam shaping methods such as diffractive optics, refractive field mapping or integration type beam shapers (homogenizers) are not effective.…”

Section: Introductionmentioning

confidence: 99%

Beam shaping of high power multimode lasers by multi-spot optics

Laskin,

Volpp,

Laskin

et al. 2024

Laser + Photonics for Advanced Manufacturing

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Significant performance improvement of modern laser technologies such as welding, additive manufacturing, brazing, cladding, sheet metal cutting, based on the use of multi-kW multimode fiber lasers, fiber-coupled solid-state and diode lasers, can be improved using beam shaping optics providing optimal energy distribution by splitting the laser beam into several beamlets creating by further focusing separate multiple spots in the working plane and variable sharing energy between these spots. Various multi-spot patterns, such as square, line, rhombus, consisting of 4 or 9 separate spots, allow eliminating or reducing spatter, realizing optimum temperature distribution in the melt pool and stabilizing the processes in welding of tailored blanks, copper and aluminium parts in the production of batteries, zinc coated steel, cladding. Multimode lasers are characterized by low spatial coherence (large BPP or M² values), therefore the most reliable optical approach to control the intensity distribution is imaging the fiber end with a collimator and a focusing objective. The proposed multi-spot beam shaping method presents a combination of fiber end imaging and geometrical separation of focused spots perpendicular to the optical axis, thus creating a compound working spot, called as quattroXX-spot or peaXXus-spot, as a combination of several spots. Varying the energy portions in separate spots and the distances between them make it possible to optimize for a particular application common intensity distribution of the compound spot. To ensure reliable operation with multi-kW lasers and to avoid optics damage the multi-focus optical devices are designed as refractive elements with smooth optical surfaces made of optical materials self-compensating thermo-optical effects that provides insignificant thermal lensing and, hence, negligible thermal focus shift and spherical aberration. The paper presents the proposed multi-spot optics, shows intensity profile measurements and application results.

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“…Later, cut quality enhancements were reported for fiber laser cutting mild and stainless steels in 12 mm thickness by use of beam oscillation methods [21]. Pang and Haecker [22] introduced optical setups with annular intensity distributions for disk laser cutting and achieved burr-free cuts in 10 mm stainless steel. However, corresponding roughness values were not mentioned.…”

Section: Introductionmentioning

confidence: 99%

Factorial Analysis of Fiber Laser Fusion Cutting of AISI 304 Stainless Steel: Evaluation of Effects on Process Performance, Kerf Geometry and Cut Edge Roughness

2021

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Factorial Design-of-Experiment analyses were applied for conventional and beam oscillation fiber laser cutting of 10 mm thick AISI 304 stainless steel. Considered factors in case of the conventional process with a static beam involve both laser and cutting gas parameters, in particular the laser power, the focal plane position, the cutting gas pressure, the nozzle stand-off distance as well as the nozzle diameter. The conducted trials were evaluated with respect to the achievable cutting speed, the cut kerf geometry and the cut edge roughness. Noticeable correlations between cut edge roughness and cut kerf geometry stimulated the development of a corresponding Computational Fluid Dynamics (CFD) model of the cutting gas flow through the kerf. A specific approach of data synchronization revealed that the experimentally determined roughness values do well correlate with numerically computed values of the backward directed component of the gas-induced shear stress and that the cut kerf geometry as internal process-inherent boundary condition influences relevant cutting characteristics more than controllable external cutting gas parameters. Finally, effects of circular beam oscillation were investigated by an additional factorial analysis considering the laser power, the focal plane position, the oscillation frequency and the oscillation amplitude as factors. The results demonstrate the potential of beam oscillation techniques for quality improvements in laser cutting.

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Laser Cutting with annular intensity distribution

Cited by 18 publications

References 9 publications

Double axicons to maximize Optical Feeder Links transmission on conventional telescopes

Double axicons to maximize Optical Feeder Links transmission on conventional telescopes

Beam shaping of high power multimode lasers by multi-spot optics

Factorial Analysis of Fiber Laser Fusion Cutting of AISI 304 Stainless Steel: Evaluation of Effects on Process Performance, Kerf Geometry and Cut Edge Roughness

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