Imaging-based amplitude laser beam shaping for material processing by 2D reflectivity tuning of a spatial light modulator

Adaptive optics are becoming a valuable tool for laser processing, providing enhanced functionality and flexibility for a range of systems. Using a single adaptive element, it is possible to correct for aberrations introduced when focusing inside the workpiece, tailor the focal intensity distribution for the particular fabrication task and/or provide parallelisation to reduce processing times. This is particularly promising for applications using ultrafast lasers for three-dimensional fabrication. We review recent developments in adaptive laser processing, including methods and applications, before discussing prospects for the future.

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“…5c. The flat top beams generated using AO have been successfully used for surface machining in a wide variety of materials 74–77 (Fig. 5d).…”

Section: Implementations Of Ao In Dlwmentioning

confidence: 99%

Adaptive optics in laser processing

2019

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“…For many laser applications, having user-defined intensity distributions may be sufficient to achieve the expected results. For this reason, beam shaping is often associated only with amplitude modulation [7][8][9]. However, since laser beams are described by complex mathematical expressions, full control over them can only be achieved if we are able to change their intensity and wavefront (phase) at will, simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Dynamic freeform diffractive lens

Mendoza-Yero¹

2023

Preprint

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In the framework of the scalar theory of diffraction a surface-pixeled convergent lens for arbitrary amplitude and phase modulation along the depth of focus is introduced. This complex diffractive lens is computer-generated from an exact solution of the inverse focal shaping problem obtained by using the Fresnel diffraction integral. The spatial multiplexing technique of double-phase method is employed to encode the complex diffractive lens into a phase optical element that can be dynamically implemented with a commercial liquid-crystal spatial light modulator. The optical surface of this lens, capable of generating not only a single axial focus but also multiple parallel foci, has neither linear nor rotational symmetry but phase jumps from one pixel to another. In addition to intensity shaping, the introduced lens provides simultaneous control over the phase of light along the depth of focus, which can be very attractive for improving and/or developing photonic applications related to the interaction of coherent laser beams with matter.

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“…As a programmable diffractive optical device, spatial light modulator (SLM) can flexibly adjust the intensity, phase and polarization of the incident beam so that many researchers use SLM for ultrafast laser beams shaping and micromanipulation [11], [12], [13]. Some researchers have loaded holograms of binary geometric masks or grey-scale masks on the SLM to shape the input laser beam into a desired profile and intensity distribution, and then reconstructed at an imaging plane with a size comparable with the beam waist at the focal plane [14], [15], [16].…”

Section: ⅰ Introductionmentioning

confidence: 99%

Flattop Beam Shaping Using Hybrid Gratings

et al. 2022

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A new method of laser beam shaping with hybrid gratings is presented. The hybrid gratings consist of a blazed grating and a gradient binary grating. The blazed grating is used to separate the incident Gaussian beam into zero order and nonzero diffraction orders. A filter is used to block the nonzero order beams and obtain the zero orders with the desired shape. The gradient binary grating is used to improve the energy distribution of the inside area of the geometric shape. A phase hologram designed with the desired shape and hybrid gratings, is loaded on a phase-only spatial light modulation to achieve arbitrary geometric flattop shapes with high uniformity. Squared and hexagonal shaping experiments demonstrated that the presented method can convert a Gaussian beam into a flattop beam with steepness edge and high uniformity. Experimental results show that the beam non-uniformity is less than 0.037.

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Imaging-based amplitude laser beam shaping for material processing by 2D reflectivity tuning of a spatial light modulator

Cited by 22 publications

References 24 publications

Adaptive optics in laser processing

Adaptive optics in laser processing

Dynamic freeform diffractive lens

Flattop Beam Shaping Using Hybrid Gratings

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