Direct fabrication of compound-eye microlens array on curved surfaces by a facile femtosecond laser enhanced wet etching process

We report a directfabrication of an omnidirectional negative microlens array on a curved substrate by afemtosecond laser enhanced chemicaletching process, which is utilized as a molding template for duplicating bioinspired compoundeyes. Thefemtosecond laser treatment of the curvedglass substrate employs a commonx-y-z stage without rotating the sample surface perpendicular to thelaser beam, and uniform, omnidirectional-aligned negativemicrolenses are generated after a hydrofluoric acidetching. Using the negative microlens array on the concaveglass substrate as a molding template, wefabricate an artificial compoundeye with 3000 positivemicrolenses of 95-μm diameter close-packed on a 5-mmpolymer hemisphere. Compared to the transferring process, the negativemicrolenses directlyfabricated on the curved mold by our method are distortion-free, and the duplicated artificialeye presents clear and uniform imaging capabilities. This work provides a facile and efficient route to thefabrication ofmicrolenses on any curved substrates without complicated alignment and motion control processes, which has the potential for the development of new microlens-based devices and systems.

Source: Applied Physics Letters - December 2, 2016 Category: Physics Authors: Hao Bian, Yang Wei, Qing Yang, Feng Chen, Fan Zhang, Guangqing Du, Jiale Yong and Xun Hou Source Type: research