A new method for fabricating high density and large aperture ratio liquid microlens array

Conventional liquid microlens arrays are facing bottlenecks in controlling droplet size and shape, and limited aperture ratio. We report a new liquid/solvent approach to overcome these obstacles for making uniform droplet array and achieving approximately 90% aperture ratio. The droplets are very stable due to the pinning effect of the polymer walls and substrate surfaces. Using the fabricated droplet array, we demonstrate a tunable-focus microlens array based on dielectrophoretic effect. The microlens array exhibits a large dynamic range and fast response time (tens of milliseconds). Besides liquid microlens arrays, this fabrication method also opens a new door for making other tunable photonic devices.