Research > 2016 - 2017 Colloquium Series

Rafael Piestun, University of Colorado, Boulder

Overcoming diffraction and multiple-scattering limitations in optical imaging

May 23, 2017 10:30am - 11:20am
EEB 105

Host: Arka Majumdar

Abstract

Optical computational imaging seeks enhanced performance and new functionality by the joint design of illumination, optics, detectors and reconstruction algorithms. Two remarkable examples discussed here enable overcoming the diffraction limit and imaging through complex media.

Abbe’s resolution limit has been overcome after more than 130 years enabling unprecedented opportunities for optical imaging at the nanoscale. Fluorescence imaging using photoactivatable or photoswitchable molecules within computational optical systems offers single molecule sensitivity within a wide field of view. The advent of three-dimensional point spread function engineering associated with optimal reconstruction algorithms provides a unique approach to further increase resolution in three dimensions.

Focusing and imaging through strongly scattering media has also been accomplished recently in the optical regime. By using a feedback system and optical modulation, the resulting wavefronts overcome the effects of multiple scattering upon propagation through the medium. In particular, a phase-control holographic technique helps characterize scattering media at high-speed using micro-electro-mechanical technology, allowing focusing through a temporally dynamic, strongly scattering sample. Further, our recent investigations demonstrate the possibility of non-invasively imaging objects through a scattering medium using the photoacoustic effect while keeping the optical resolution.

Biography

Photo of Rafael Piestun Rafael Piestun received MSc. and Ph.D. degrees in electrical engineering from the Technion – Israel Institute of Technology. From 1998 to 2000 he was a researcher at Stanford University. Since 2001 he has been with the Department of Electrical and Computer Engineering and the Department of Physics at the University of Colorado – Boulder. Professor Piestun is a fellow of the Optical Society of America, was a Fulbright scholar, an Eshkol fellow, received a Honda Initiation Grant award, a Minerva award, a Provost Achievement Award and El-Op and Gutwirth prizes. He served in the editorial committee of Optics and Photonics News and was associate editor for Applied Optics. He was the director and principal investigator of the NSF-IGERT program in Computational Optical Sensing and Imaging at the University of Colorado and is co-principal investigator of the STROBE NSF Science and Technology Center. His areas of interest include computational optical imaging, superresolution microscopy, volumetric photonic devices, scattering optics and ultrafast optics.


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