Additive Manufacturing of Metal Micro-ring and Tube by Laser-Assisted Electrophoretic Deposition with Laguerre-Gaussian Beam

We report a method for laser-assisted electrophoretic deposition using a Laguerre-Gaussian beam for maskless patterning of metal rings and tubes.These are structures of utmost importance,particularly in photonic devices.Metal nanoparticles,which are gathered in a colloidal solution by a laser trapping technique,are deposited on a substrate via electrophoresis.The deposition pattern is dependent on the focused spot shape during laser trapping.The intensity distribution of the Laguerre-Gaussian beam is ring-shaped.Rings with different inner diameters can be fabricated by varying the topological charge of the Laguerre-Gaussian beam.The equivalent inner diameters of the deposited rings with topological charges of 1,3,and 5 were 0.30,0.78,and 1.45μm,respectively.The inner diameter of the deposited ring with a topological charge of 1 was smaller than the wavelength of the laser beam(532 nm).A tube was also fabricated with a topological charge of 3 by vertical displacement of the deposition cell.The deposition technology developed here using Laguerre-Gaussian beam will contribute to advancements in the fabrication of photonic and nano-fluidic devices.