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Ultrafast three-dimensional printing of optically smooth microlens arrays by oscillation assisted digital light processing.

Microlens array has become an important micro-optics device in various applications. Compared with traditional manufacturing approaches, DLP based printing enables fabrication of complex 3D geometries and is a possible manufacturing approach for microlens arrays. However, the nature of 3D printing objects by stacking successive 2D patterns formed by discrete pixels leads to coarse surface roughness and makes DLP based printing unsuccessful in fabricating optical components. Here, we report an oscillation assisted DLP based printing approach for fabrication of microlens arrays. Optically smooth surface (about 1 nm surface roughness) is achieved by mechanical oscillation that eliminates the jagged surface formed by discrete pixels, and a 1-3 seconds single grayscale UV exposure that removes the staircase effect. Moreover, computationally designed grayscale UV patterns allow us to fabricate microlenses with various profiles. The proposed approach paves a way to 3D print optical components with high quality, fast speed and vast flexibility.