1. Liquid Lenses and Prisms for Adaptive Optics and Beam Steering
We have several projects where we are developing liquid optics components based on the electrowetting effect, where the contact angle of a liquid changes due to applied voltage. Optical lenses and prisms can be fabricated as individual components or as arrays and are electrically addressed by individual transparent electrodes over each cavity. By applying a voltage between the liquid and the substrate, the droplet changes curvature and the liquid interface acts as a variable focus lens or with multiple electrodes as a prism. This phenomenon can be used for curvature and phase compensation in adaptive optics, communications, beam steering, optical switching and microscopy. Funding Sources: Office of Naval Research (ONR), Defense Advanced Research Projects Agency (DARPA), National Science Foundation (NSF), NSF/IUCRC MAST (Membrane Science Engineering and Technology Research Center)
Example of Electrowetting Lens Operation
2. Atomic Layer Deposition (ALD) Enabled Nano Electromechanical Systems (NEMS)
Atomic layer deposition (ALD) and Atomic Layer Etching (ALE) are self-limiting processes that enable accurate atomic-scale thickness control either through deposition or etching of various materials at temperatures typically lower than 200 degrees Celcius. This makes ALD and ALE ideal candidates for forming of coatings or structural/mechanical layers in MEMS and nano-electromechanical systems. We are developing novel materials and manufacturing processes that demonstrate that ALD can be used as a structural layer and can be compatible with standard IC processing. Alumina, zinc oxide, titanium oxide, silicon oxide, vanadium oxide, tungsten, and ruthenium are just some examples of the materials being currently studied.
Funding Sources: Defense Advanced Research Projects Agency (DARPA), NSF
3. MEMS and Electronics Packaging and Integration Examples
We are working on a novel technology to realize mechanical assembly of parts using micropatterned surfaces based on ALD structures. The parts can be press-fit together to achieve a physical bond among structures through mechanical adhesion with service temperatures greater than 400°C. This also simplifies labor and energy consumption in fabrication of complex composite or 3D parts. The technology is similar to Lego, but uses microfabricated parts. (more information on this project can be found in the following publication: J. Brown and V. Bright, IEEE J. Microelectromechanical Systems, vol. 25, no. 2, 2016).
Multiphoton Electrowetting Fiber-Coupled Microscope for 3D Imaging in the Brain
We are developing a lightweight fiber-coupled confocal fluorescence microscope that incorporates an electrowetting variable focus lens to provide axial scanning for full three-dimensional (3D) imaging. Lateral scanning is accomplished by coupling our device to a laser-scanning confocal microscope through a coherent imaging fiber bundle. The optical components of the device are combined in a custom 3D-printed adapter with an assembled weight of less than 2 grams that can be mounted onto the head of a mouse. (more information on this project can be found in the following publication: B. Ozbay, et al., Optics Letters, vol. 40, no. 11, 2015).