Laser 3D processing (Invited Paper)

As a direct-write energy source, the laser has been a foundational tool in 3D material processing for nearly 50 years. 3D structures have been fabricated by both additive and subtractive approaches at spatial resolutions that now go well below the processing-laser wavelength. Complex shape structures have been fabricated by use of gas or liquid phase laser photochemistry or by the direct fusion of particles/powders. 3D structures can also be produced by stacking building blocks as by laser induced forward transfer or by optical tweezers. Finally, structures can be produced by altering the properties of the stock material itself to enhance removal by chemical means. In 3D growth of biological material, laser processing is used to build the scaffold on to which biological matter grows. Technologies that have enabled this wide array of organic and inorganic material processing capabilities include significant refinements in stage motion control and automation, developments that have produced lasers with stable power over a wide range of powers and wavelengths, shaping of the laser beam and temporal pulse permits local metering of the delivered energy, and modeling and simulation software that calculate the incident local electromagnetic field and tools that parse a 3D CAD model into a series of laser material processing steps. We will present an overview of laser 3D material processing/printing over the many years and discuss prospects of lasers and laser applications.