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Proceedings Paper

Control of energy density inside turbid medium (Conference Presentation)
Author(s): Raktim Sarma; Alexey Yamilov; Sasha Petrenko; Yaron Bromberg; Hui Cao

Paper Abstract

Recent breakthroughs in optical wavefront engineering have opened the possibility of controlling light intensity distribution inside highly scattering medium, but their success is limited by the open geometry of the sample and the difficulty of covering all input modes. Here we demonstrate experimentally an efficient control of energy density distribution inside a strong scattering medium. Instead of the open slab geometry, we fabricate a silicon waveguide that contains scatterers and has reflecting sidewalls. The intensity distribution inside the 2D waveguide is probed from the third dimension. With a careful design of the on-chip coupling waveguide, we can access all the input modes. Such unprecedented control of incident wavefront leads to 10 times enhancement of the total transmission or 50 times suppression. A direct probe of light intensity distribution inside the disordered structure reveals that selective excitation of open channels leads to an energy buildup deep inside the scattering medium, while the excitation of closed channels greatly reduces the penetration depth. Compared to the linear decay for random input fields, the optimized wavefront can produce an intensity profile that is either peaked near the center of the waveguide or decay exponentially with depth. The total energy stored inside the waveguide is increased 3.7 times or decreased 2 times. Since the energy density dictates light-matter interactions inside a scattering system, our results demonstrate the possibility of tailoring optical excitations as well as linear and nonlinear optical processes inside the turbid medium in an on-chip platform.

Paper Details

Date Published: 24 April 2017
PDF: 1 pages
Proc. SPIE 10073, Adaptive Optics and Wavefront Control for Biological Systems III, 100730Q (24 April 2017); doi: 10.1117/12.2251457
Show Author Affiliations
Raktim Sarma, Yale Univ. (United States)
Alexey Yamilov, Missouri Univ. of Science and Technology (United States)
Sasha Petrenko, Missouri Univ. of Science and Technology (United States)
Yaron Bromberg, Yale Univ. (United States)
Hui Cao, Yale Univ. (United States)

Published in SPIE Proceedings Vol. 10073:
Adaptive Optics and Wavefront Control for Biological Systems III
Thomas G. Bifano; Joel Kubby; Sylvain Gigan, Editor(s)

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