Created by sebastien.popoff on 23/09/2021
Spatiotemporal control of light
Joel A. Carpenter
This tutorial investigates various techniques for spatial and/or temporal optical beam manipulation.
Created by sebastien.popoff on 14/07/2021
Learning and Avoiding Disorder in Multimode Fibers
Sébastien M. Popoff
In this work, we demonstrate the existence of a set of spatial channels in multimode fibers that are robust to strong local perturbations. We show that, even for a high level of disorder, light propagation can be characterized by just a few key properties.
Related article: doi.org/10.1103/PhysRevX.11.021060
Created by sebastien.popoff on 12/06/2020
Time reversed optical waves by arbitrary vector spatiotemporal field generation
Mickael Mounaix, Nicolas K. Fontaine, David T. Neilson, Roland Ryf, Haoshuo Chen, Juan Carlos Alvarado-Zacarias and Joel Carpenter
This video published on J. Carpenter Youtube Channel explained the details of the experiment of this paper [Mounaix et al., arxiv, 1909.07003, (2019)]. The authors use spatial and spectral shaping with a spatial light modulator to achieve spatio-temporal focusing of light by time-reversal through a multimode fiber.
Created by sebastien.popoff on 22/06/2019
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.