Thermally Adjustable Microlenses for Biological Imaging

A simple and efficient tunable microlens capable of thermally adjusting its focal length is presented. The polymeric solid-state lens is created by exposing a droplet of SU-8 to UV-light. Then by altering the temperature of the microlens through a heating scheme on the substrate, we actively control the material through the curvature and magnification of the lens without the need for complicated mechanical components. Furthermore, we demonstrate the ability to use the microlens in a variety of applications including real-time biological imaging in both aqueous and non-aqueous environments. This method has potential applications in fields including biomaterials, tunable laser systems, functional biomimetics, and endoscopy.