High-Fidelity Wavefront Shaping for Coherent Light Control in Multimode Fibers

Wavefront shaping enables precise focusing of light through multimode fibers, significantly improving imaging methods for single-fiber-based imaging and endoscopy. When the input light field is perfectly controlled, all transmitted power can be efficiently focused at specific target locations, achieving an enhancement factor equal to the number of input degrees of freedom, N.

In this webinar, Hasan Yilmaz will present a comprehensive work combining theoretical predictions and experiments to determine the upper bounds of the enhancement factor for focusing light through multimode fibers. Theoretically, he derives these bounds using mode decomposition and introduce the input participation ratio, which quantifies the fraction of degrees of freedom contributing to phase-only modulation of the input wavefront. Yilmaz’s analysis shows that the participation ratio strongly depends on the basis on which phase modulation is applied.

Experimentally, Yilmaz measures the field transmission matrix using common-path phase-shift interferometry. He applies the stepwise sequential algorithm in the canonical SLM pixel basis and the dual-reference algorithm in the Hadamard basis. He then evaluates how noise and transmission matrix decorrelation affect the enhancement factor, finding that the Hadamard basis improves enhancement due to better signal-to-noise properties. This work provides insights into the fundamental limits of phase-only shaping, with implications for fiber-optic imaging and broad-area fiber amplifiers.

Subject Matter Level: Introductory - Assumes little previous knowledge of the topic

What You Will Learn:
• Light propagation through multimode fibers
• Wavefront shaping for ccoherent ontrol of light propagation-Single-fiber imaging

Who Should Attend:
• Graduate students
• Researchers at universities and industry
• Professors

About the Presenter: Hasan Yilmaz from Bilkent University

Hasan Yılmaz is an Assistant Professor at the UNAM - Institute of Materials Science and Nanotechnology at Bilkent University, where he founded and leads the Emergent Complex Optical Systems Laboratory. His research focuses on the physics and applications of complex photonic systems at the intersection of optics, statistical physics, and condensed matter physics. Previously, he was a postdoctoral associate and associate research scientist in Prof. Hui Cao’s lab at Yale University. He received his Ph.D. in 2015 from the University of Twente in the Netherlands, working with Prof. Allard Mosk on “Advanced Optical Imaging with Scattering Lenses.” He completed his M.Sc. in Materials Science and Engineering at Koç University in 2011, and earned his B.Sc. in Physics Engineering from İstanbul Technical University in 2008.