Fabrication of bioinspired omnidirectional and gapless microlens array for wide field-of-view detections

Microlens arrays on curvilinear surfaces are highly desirable for wide field-of-view imaging and sensing systems. However, it is technically challenging to fabricate these structures. This letter reports a simple method to machine close-packed microlenses on curvilinear surfaces as inspired by the insect eyes, which involves a femtosecond-laser-based microfabrication and a thermomechanical bending process. Over 7600 hexagonal-shaped microlenses with a diameter of 50 μm were fabricated on a hemispherical poly (methyl methacrylate) shell, which is similar to the compound eyes of insects. The optical performances of the microlens array were demonstrated by the abilities of high-resolution imaging and large view-angle focusing.