Direct Fabrication of Microlens Arrays on PMMA with Laser-Induced Structural Modification

Reported here is the direct fabrication of the convex microlens arrays on poymethylmethacrylate using laser-induced structural modification. Based on single femtosecond pulse in situ modification, sixty thousand convex microlenses, whose diameters was <12μm , could be fabricated per minute, exhibiting much higher efficiency than conventional laser direct writing technique. The formation mechanism was mainly attributed to photodecomposition, which would result in the scission of polymer chains. The shape of microlenses could be tuned by the laser power. In addition, the good optical performance of the microlens was revealed by its ability of high resolution imaging. This technique may open up a new way of preparing low-cost and large-area convex structure which is widely used in many advanced microdevices, such as lab-on-chips and biomimetic compound eyes.