Speaker:

Prof. Rafael Piestun, university of Colorado

Gathering - 12:30

Lecture – 13:00-14:00

Auditorium 011, Engineering Class Room Building,

Faculty of Engineering, Tel-Aviv University

Abstract:

Optical computational imaging seeks enhanced performance and new functionality by the joint design of illumination, unconventional 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 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, or a multimode fiber. 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. We will discuss implications for ultrathin optical endoscopy and adaptive nonlinear wavefront shaping.