Fabrication of close-packed microlens array with superhydrophobicity and high imaging performance

Microlens arrays (MLAs) with special functions such as superhydrophobicity and self-cleaning ability are highly desired in the micro-optical system which is often used in easily polluted environment. In this paper, a new method is demonstrated to fabricate the MLAs with a high fill factor and superhydrophobicity. The method combines femtosecond laser wet etching, polydimethylsiloxane (PDMS) replication and subsequently femtosecond laser direct writing process. The fabricated MLAs decorated with micro/nanoscale hierarchical structures compared with the normal MLAs. Water droplets on the as-prepared surfaces exhibit superhydrophobicity and ultralow adhesion which endows the fabricated samples possess self-cleaning property. The as-fabricated MLAs could find their applications in bioscience research, ocean exploration, endoscopic surgery, microfluidic system, etc.