High-Performance NIR Laser-Beam Shaping and Materials Processing at 350 W with a Spatial Light Modulator

Zuo, S ORCID: 0009-0000-2922-7856, Wang, S, Pulham, C ORCID: 0009-0000-7877-8478, Tang, Y ORCID: 0009-0006-6486-5187, Perrie, W, Allegre, OJ ORCID: 0000-0002-8593-128X, Tang, Y, Sharp, M ORCID: 0000-0001-9687-4703, Leach, J, Whitehead, DJ, Bilton, M ORCID: 0000-0002-0475-2942, Mirihanage, W ORCID: 0000-0002-9083-269X, Mativenga, P, Edwardson, SP ORCID: 0000-0001-5239-4409 and Dearden, G (2025) High-Performance NIR Laser-Beam Shaping and Materials Processing at 350 W with a Spatial Light Modulator. Photonics, 12 (6).

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Abstract

Shaping or splitting of a Gaussian beam is often desired to optimise laser–material interactions, improving throughput and quality. This can be achieved holographically using liquid crystal-on-silicon spatial light modulators (LC-SLMs). Until recently, maximum exposure has been limited to circa 120 W average power with a Gaussian profile, restricting potential applications due to the non-linear (NL) phase response of the liquid crystal above this threshold. In this study, we present experimental tests of a new SLM device, demonstrating high first-order diffraction efficiency of η = 0.98 ± 0.01 at 300 W average power and a phase range Δφ > 2π at P = 383 W, an exceptional performance. The numerically calculated device temperature response with power closely matches that measured, supporting the higher power-handling capability. Surface modification of mild steel and molybdenum up to P = 350 W exposure is demonstrated when employing a single-mode (SM) fibre laser source. Exposure on mild steel with a vortex beam (m = +6) displays numerous ringed regions with varying micro-structures and clear elemental separation created by the radial heat flow. On molybdenum, with multi-spot Gaussian exposure, both MoO3 films and recrystallisation rings were observed, exposure-dependent. The step change in device capability will accelerate new applications for this LC-SLM in both subtractive and additive manufacturing.

Item Type:	Article
Uncontrolled Keywords:	5102 Atomic, Molecular and Optical Physics; 51 Physical Sciences; 5102 Atomic, molecular and optical physics
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Divisions:	Engineering
Publisher:	MDPI
Date of acceptance:	26 May 2025
Date of first compliant Open Access:	5 June 2025
Date Deposited:	05 Jun 2025 11:13
Last Modified:	03 Jul 2025 13:01
DOI or ID number:	10.3390/photonics12060544
URI:	https://researchonline.ljmu.ac.uk/id/eprint/26524

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