Dr. Ori Katz

Dr. Ori Katz joined the Hebrew University’s Department of Applied Physics as a senior researcher in the summer of 2015. Dr. Katz completed his postdoctoral research in Paris, at Institut Langevin and Laboratoire Kastler Brossel. He received his PhD in Physics from the Weizmann Institute of Science, after completing his first two degrees at the Hebrew University, graduating cum-laude in both. Before joining the Hebrew University Dr. Katz was the recipient of the Israel Physical Society Prize for Graduate Student in experimental physics, the Rothschild Fellowship and the Marie Curie Fellowship for career development (IEF). Dr. Katz joins the Hebrew University as a prestigious Azrieli Foundation Faculty Fellow and since his arrival he has been awarded a 2015 European Research Council (ERC) Starting Grant.

The research in Dr. Katz’ lab lies at the interface between physics and engineering and focuses on developing novel computational-based optical imaging techniques to overcome the limitations of current approaches. His methods challenge some intuitive notions on randomly scattered light, such as the light reflected off walls or diffuses through frosted glass windows, by showing that it is possible to extract information from scattered light for imaging. The techniques developed in Katz’s lab will allow us not only to measure scattered light but also to undo it and in some situations to exploit it for practical imaging and sensing even applications in diverse fields from biomedicine to defense.

Website – https://scholars.huji.ac.il/orikatz


Imaging with scattered light


Random scattering of light in complex samples such as biological tissue renders most objects opaque to optical imaging techniques. However, although random, scattering is a deterministic process, and it can be undone, and also exploited by controlling the incident optical wavefront. These insights form the basis for the emerging field of optical wavefront-shaping [1]. Opening the path to new possibilities, such as imaging through visually opaque samples and around corners [2].
However, two major challenges exist in the field today: the first is how to determine the required wavefront correction without accessing the far (target) side of the scattering sample. The second is how to do it faster than the dynamics of the sample decorrelation time.
I will present some of our recent efforts in addressing these challenges [3-11]. These include the use of optical nonlinearities [3], the photoacoustic effect [4-6], and acousto-optics [7-8] to non-invasively focus light or perform imaging scattering samples, exploiting the dynamics of the sample instead of fighting them. I will also show how by exploiting inherent correlations of scattered light, it is possible to image through scattering layers and ‘around corners’ using nothing but a smartphone camera [9].
If time permits, I will present the use of these principles for endoscopic imaging through optical fibers [10-11].

[1] A.P. Mosk et al., “Controlling waves in space and time for imaging and focusing in complex media”, Nature Photonics 6, 283 (2012).
[2] O. Katz et al., “Looking around corners and through thin turbid layers in real time with scattered incoherent light”, Nature Photonics 6, 549 (2012).
[3] O.Katz et al., “Noninvasive nonlinear focusing and imaging through strongly scattering turbid layers”, Optica, 1, 3, 170-174 (2014).
[4] T. Chaigne et al. “Controlling light in scattering media noninvasively using the photo-acoustic transmission-matrix.”, Nature Photonics 8, 58 (2014).
[5] E.Hojman et al. “Photoacoustic imaging beyond the acoustic diffraction-limit with dynamic speckle illumination and sparse joint support recovery”, Optics Express Vol. 25, Issue 5, pp. 4875-4886 (2017)
[6] T. Chaigne et al. “Super-resolution photoacoustic imaging via flow-induced absorption fluctuations”, Optica Vol. 4, Issue 11, pp. 1397-1404 (2017)
[7] O. Katz et al. ” Controlling light in complex media beyond the acoustic diffraction-limit using the acousto-optic transmission matrix”, Nature Communications (2019)
[8] D. Doktofsky et al. “Acousto-optic tomography beyond the acoustic diffraction-limit using speckle decorrelation”, arXiv: 1812.00400.
[9] O. Katz et al., “Non-invasive single-shot imaging through scattering layers and around corners via speckle correlations”, Nature Photonics, 8, 784–790 (2014)
[10] A.Porat et al., “Widefield lensless imaging through a fiber bundle via speckle-correlations”, Optics Express (2016)
[11] U.Weiss et al., “Two-photon lensless micro-endoscopy with in-situ wavefront correction” Optics Express Vol. 26, Issue 22, pp. 28808-28817 (2018).