This project focuses on (1) the development of light-responsive tunable liquid microlenses actuated by light-responsive hydrogels with large focal length tuning range and sub-seconds of tuning time, and integration of such tunable microlenses into fiber optics to realize a prototype endoscope with large scanning range; and (2) a coherent interdisciplinary program integrating high quality teaching and outreach activities with research. In the proposed microlenses, hydrogel microstructures undergo volumetric changes when exposed to light of certain wavelengths and serve as microactuators to tune the shape of liquid-liquid menisci, changing the focal length of the microlenses thus formed. The research program includes (1) design, fabrication and characterization of tunable liquid microlenses on glass substrates activated by light-responsive hydrogels that are thermo-responsive hydrogels incorporating gold colloids and nanoshells; (2) development of a prototype endoscope by integrating the light-responsive tunable microlenses into fiber optics; and (3) investigation on improving the adhesion between the light-responsive hydrogels and their interfacing surfaces for better reliability of the microlenses and the endoscope.
The research has a broad range of potential applications related to biodefense, environmental monitoring and public health. The hydrogel-based microlens system can incorporate many hydrogels that respond to different stimuli to be used as physical, biological, or chemical sensors. This research will make significant contributions to variable-focus microoptics for optical imaging and microanalytics, which have wide applications in medical diagnostics, biophotonics and lab-on-a-chip technologies. It will also contribute to microfluidics, especially optofluidics, and ophthalmology. The proposed project will generate significant educational opportunities for students at both college and K-12 levels. The education and outreach components of this project include improving existing curriculum, developing new interdisciplinary courses, mentoring undergraduate and graduate students, especially underrepresented students, and dissemination and outreach to the local community and general public on science and engineering through many outlets.
