Dry etching-assisted femtosecond laser fabrication of silicon-based microlens arrays

The growing importance of micro-lens arrays (MLAs) in advanced optical applications necessitates robust procedures for fabricating high-precision components. Here, we present a composite manufacturing approach for silicon-based MLAs that combines femtosecond laser modification with dry etching. A systematic investigation was conducted to elucidate how laser parameters (single-pulse energy, pulse number) and etching conditions (SF₆ flow rate, time) affect microlens morphology and surface quality. This knowledge enabled the successful fabrication of three distinct MLAs that consistently met all design specifications, featuring microstructure dimensional errors below 3%, surface roughness under 5nm, and macroscopic uniformity exceeding 95%. Our work establishes a foundational and instructive framework for the precision manufacturing of silicon-based micro-optical elements.