Diffractive Optical Elements in Laser Processing: Beam Shaping, Nanostructuring, and Digital Innovations

Diffractive optical elements (DOEs) have emerged as a powerful toolset for advancing laser-based material processing by enabling precise control of spatial energy distribution. Through engineered phase modulation, DOEs generate tailored irradiance profiles such as flat-top, ring, or multi-spot beams, supporting uniform heating, multi-zone thermal treatment, and defect-minimized welding and joining of metallic and composite materials. Experimental and modeling studies demonstrate their effectiveness in refining microstructures, reducing hardness gradients, enhancing wear resistance, and improving joint quality across steels, titanium alloys, and metal–polymer–metal composites. Beyond macroscopic treatments, DOE-assisted laser processing facilitates the formation of nanoporous morphologies and oxide nanostructures, where controlled thermal fields, pulsed irradiation, and wave-induced mass transport enable reproducible nanoscale architectures and semiconductor heterostructures. Integration with digital engineering and artificial intelligence further extends these capabilities, providing inverse design of DOE profiles, adaptive parameter optimization, and real-time monitoring for smart material fabrication. Collectively, these advances establish DOE-based beam shaping as a cornerstone of next-generation laser manufacturing, bridging photonics, nanotechnology, and data-driven optimization to deliver programmable surfaces, enhanced material performance, and scalable industrial adoption.