Laser-assisted positioning enables efficient fabrication of flexibly arranged concave microlens arrays via precision...

Concave microlens arrays (MLAs) are critical for light uniformity, multi-focus imaging, and beam shaping, while their mass production with high precision is still costly and challenging. This study presents a novel precision glass molding (PGM) method, in which hole arrays with various layouts and intervals are firstly created by a nanosecond laser on the substrate, and then precision ceramic spheres are placed into them to form a convex mold assembly for forming flexibly arranged concave MLAs on the processed glass surface. As precision ceramic spheres can be easily assembled and replaced, failure of the entire mold caused by the local damage during PGM process can be avoided. The fabricated MLAs displayed a smooth surface (S_a≈13 nm), uniform features (σ_h = 0.95µm, σ_d = 5.96µm), low residual stress (<0.4 MPa), and excellent focusing and imaging capability, demonstrating the effectiveness of the proposed method. The rapid mass fabrication of glass optical elements for flexible MLAs also offers valuable insights for the design and production of other functional structural surfaces.