Compensating for phase drifts in holographic measurements

Digital holography allows measuring the complex amplitude of a given wavefront. We presented in detail the off-axis holography approach. However, it requires a separate reference arm. Due to air flow, vibrations, or other perturbations, the optical path length difference between the two arms can fluctuate in time, even in controlled lab experiments on a good optical table. This means that the phase of the measured wavefront is estimated up to a global phase that can randomly change over time. This is very detrimental for transmission matrix measurements as the relative phase between each column has to be precisely estimated. This is particularly true when the measurement time can take few minutes or more when using a liquid crystal spatial light modulator that has a limited frame rate. In [R. Mouthaan et al., Appl. Opt. (2022)], the authors propose a simple yet robust way to compensate for phase fluctuations, even when the phase changes completely between two frames.

Spatiotemporal control of light

Joel A. Carpenter
October 2021

Gerchberg-Saxton is a phase retrieval algorithm, which attempts to retrieve the phase corresponding to two intensity images taken in the near and far-field respectively. It can also be used for calculating computer-generated holograms (phase masks) that generate a desired.

Spatiotemporal control of light

Joel A. Carpenter
May 2021

This tutorial investigates various techniques for spatial and/or temporal optical beam manipulation.

Learning and Avoiding Disorder in Multimode Fibers

Sébastien M. Popoff
July 2021

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