"Bio-inspired Optics and Its Applications"

Guo-Dung John Su, Associate Professor, Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan

August 29th (Monday), 3:00pm
Materials Research Lab (MRL), Rm 2053

The natural world exhibits many examples of efficient design and specialized functionality. Scientists have long sought inspiration from the natural world; biomimetic design is responsible for many everyday products, for example Velcro. Inspired by the minute hooks on the seeds of the burdock plant, a synthetic mimic was made and has since found a multitude of applications. Optical biomimetics is a research discipline inspired by optical systems found in nature and by the bright appearances that often result from such systems.

In our lab, we have worked two optical components that were inspired by optical biomimetics: polymer deformable mirrors and microlens arrays. Unlike traditional auto-focus and zoom image systems that were made by a set of motor-moved lenses, we propose a thin autofocus system using a large stroke MEMS deformable mirror which has the potential to downscale the size and to minimize chromatic aberration. The module size is 5.4 mm thick in optical design layout and achieve MTF = 0.28 at spatial frequency of 230 cycles/mm. The position of clear image can vary from 4 cm to 50 cm achieved by controlling the surface curvature of the MEMS deformable mirror. We also developed a new roll-to-roll method to fabricate visible light transparent microlens arrays on a glass substrate by using soft and cost-effective polydimethylsiloxane (PDMS) molds. The PDMS molds can be made easily at a low cost compared with traditional electroplating metal molds. The results showed that the best yield rate and replication performance were achieved with a pressure of approximately 200 Newton/cm2, and four minutes of ultraviolet light exposure. The microlenses have been applied to solid state lighting and solar energy harvesting.

About Guo-Dung John Su:

Dr. Guo-Dung J. Su received a BS degree from National Taiwan University in 1992 and his MS and PhD in electrical engineering from University of California, Los Angeles in 1998 and 2001, respectively. His doctoral research interest was related to MEMS scanners with flat mirror surfaces for active optical alignment and micromirror arrays for adaptive optics. His outstanding work has been reported by the magazine “WDM solutions” in the August 2001.

In 2001, he joined Umachines, Inc. as a staff researcher responsible for the development of MEMS optical cross-connect switches. The developed product has passed the rigorous Telcordia GR-1221 tests, which only three companies in the world by the time (the other two are JDSU and DiCon) can provide such high reliability product. In 2003, his research works receive the funding awards from U.S. Air Force and NASA for continuing advanced research works in the optical MEMS fields. Dr. Guo-Dung J. Su is now an associate professor at Graduate Institute of Photonics and Optoelectronics of National Taiwan University. His current research interests include micro-optics devices, optical system design, gas sensors and surface plasmon effects in organic photovoltaic.

Hosted by: Professor Larry Coldren