Microlens With Tunable Astigmatism

A novel astigmatism-tunable microlens is reported in this letter. This device is based on a thermal-actuated current-controlled tunable polymer lens. The thermal deformation as well as surface profile of polymer lens is tuned by temperature using the current induced Joule heating. The asymmetric boundary condition is further applied on the silicon conducting ring of the lens to invoke asymmetric deformation of the polymer lens as well as astigmatic change of the polymer lens. To prove the concept, the astigmatism-tunable polydimethylsiloxane lens has been fabricated on the silicon-on-glass wafer. Astigmatism tuning was demonstrated by change of astigmatic focal distance, from 1590 to 44 mum, as input current increased from 0 to 30 mA. In addition, aspect ratios of focal spot shape were varied from -20 to -1.3 and 16 to 1.22 with respect to anterior and posterior focal points. This device provides a feasible solution to the dilemma of astigmatic tuning capability and miniaturization. In summary, the present device has the potential to act as a key component for microelectromechanical systems-based aberration corrector or laser focus-spot shaper.