Stereolithography with variable resolutions using optical filter with high-contrast gratings

A three-dimensional printing approach based on stereolithography with variable printing resolutions was invented to solve the trade-off between throughput and resolution. In this technology, the variable fabrication resolutions are achieved by switching laser wavelength. The key component to enable this technology is an optical filter based on high-contrast gratings. The optical filter has been designed and numerically studied using the finite-difference time-domain method and was fabricated using nanoimprint lithography. The minimum printing resolution of the accordingly constructed stereolithography apparatus is reduced to 37 μm. Variable pixel sizes from 37 to 417 μm have been demonstrated. Using the designed and fabricated optical filter is a promising method to optimize the manufacturing efficiency of the stereolithography process.