Harnessing disorder and symmetries in multimode fibers

Sébastien M. Popoff
IESC Cargèse, France
April 2024

We present how to study light propagation in multimode fibers using transmission matrix measurements and apply it to understand the effect disorder and its impact on the so-called rotational memory effect. This talk is part of the Wave Propagation and Control in Complex Media 2024 workshop (15-19 April 2024, Cargèse, France)

Wavefront Shaping in Complex Media for Linear Analog Computation

Sebastien M. Popoff

PR'19: Photorefractive Photonics and beyond (Gerardmer, France), June 21 2019

Abstract: Performing linear operations using optical devices is a crucial building block in many fields ranging from telecommunications to optical analog computation and machine learning. For many of these applications, key requirements are robustness to fabrication inaccuracies, reconfigurability, and scalability. Traditionally, the conformation or the structure of the medium is optimized in order to perform a given desired operation. Since the advent of wavefront shaping, we know that the complexity of a given operation can be shifted toward the engineering of the wavefront, allowing, for example, to use any random medium as a lens. We propose to use this approach to use complex optical media such as multimode fibers or scattering media as a computational platform driven by wavefront shaping to perform analog linear operations. Given a large random transmission matrix representing the light propagation in such a medium, we can extract any desired smaller linear operator by finding suitable input and output projectors. We demonstrate this concept by finding input wavefronts using a Spatial Light Modulator that causes the complex medium to act as a desired complex-valued linear operator on the optical field.