System and method to control defects in projection-based sub-micrometer additive manufacturing

A laser-based manufacturing system for fabricating non-planar three-dimensional layers, the system comprising:

• a laser for producing a laser beam with a plurality of optical wavelengths;
• a tunable mask comprising a plurality of optically dispersive elements, each optically dispersive element being configured to receive the laser beam and split the beam into a plurality of distinct beam components, wherein each said beam component has spatially separated optical spectral components;
• an optical assembly configured to collimate the distinct beam components to create a collimated beam and to focus the collimated beam into a focused laser beam, which is projected at an image plane onto or within a photopolymer resist material;
• and
• a controller operatively coupled to the tunable mask, the controller being configured by instructions to:
• direct the tunable mask to actuate a first set of plurality of optically dispersive elements to direct the tunable mask to receive a laser beam and split the beam into distinct beam components to be collimated and focused by the optical assembly to generate a first temporally focused light sheet onto or within a first region of the photopolymer resist material, wherein the first temporally focused light sheet is generated onto or within the first region for a first finite duration of time to cause a first simultaneous polymerization of a first set of selected portions of the photopolymer resist material corresponding to a first selected pattern;
• and
• direct the tunable mask to actuate a second set of plurality of optically dispersive elements to direct the tunable mask to receive the laser beam and split the beam into distinct beam components to be collimated and focused by the optical assembly to generate a second temporally focused light sheet onto or within a first region of a photopolymer resist material, wherein the second temporally focused light sheet is generated onto or within the first region for a second finite duration of time to cause a second simultaneous polymerization of a first set of selected portions of the photopolymer resist material corresponding to a first selected pattern,
• wherein the first temporally focused light sheet and the second temporally focused light sheet collectively illuminate a continuous region on or in the photopolymer resist material in a depth direction of the photopolymer resist material that includes the first region and the second region.

A non-transitory computer readable medium having instructions stored thereon, wherein execution of the instructions by a processor causes the processor to:

• receive a first image having a plurality of pixels corresponding to a first pattern to project on and into a photopolymer resist material in an additive manufacturing operation to form a first layer of a structure;
• receive a second image having a plurality of pixels corresponding to a second pattern to project on and into the photopolymer resist material in the additive manufacturing operation to form the first layer of the structure;
• direct, based on the first image, a tunable mask to generate a first temporally focused light sheet according to the first pattern;
• and
• direct, based on the second image, the tunable mask to generate a second temporally focused light sheet according to the second pattern,
• wherein the first temporally focused light sheet is generated onto or within a first region of the photopolymer resist material for a first finite duration of time to cause a first simultaneous polymerization of a first set of selected portions of the photopolymer resist material corresponding to the first pattern,
• wherein the second temporally focused light sheet is generated onto or within a second region of a photopolymer resist material for a second finite duration of time to cause a second simultaneous polymerization of a second set of selected portions of the photopolymer resist material corresponding to the second pattern,
• wherein the first temporally focused light sheet and the second temporally focused light sheet are collectively illuminated on or into a continuous region in the photopolymer resist material in a depth direction of the photopolymer resist material that includes the first region and the second region, and
• wherein each of the first temporally focused light sheet and the second temporally focused light sheet is generated by directing a respective laser beam to a tunable mask and actuating a plurality of optically dispersive elements of the tunable mask to split the respective laser beam into distinct beam components to be collimated and focused to the first region and the second region, respectively.