Debye lunch lecture - dr. Dorian Bouchet (Nanophotonics)

Title: Maximum information states for coherent scattering measurements

Abstract:
The use of coherent light for precision measurements has driven important progress in research fields from biomedical optics to semiconductor manufacturing. However, performing precise estimations of a given observable can be challenging due to the complex scattering processes typically encountered in realistic systems. Using the external degrees of freedom provided by wavefront-shaping techniques to maximize the Fisher information available to the observer, we experimentally demonstrate a direct approach to generate optimal coherent states of light for parameter estimation, regardless of the complexity of the system. Such light states are shown to be spatially optimized not only with respect to the specific observable of interest, but also with respect to the position of the observer. As an example, we apply the method to estimate the phase shift induced by an object that is hidden behind a disordered medium, with a precision improved by an order of magnitude as compared to what can be achieved with unoptimized states. These results could find interesting applications to improve the performance of metrology and imaging techniques in random and engineered complex scattering materials.

Published paper:
Maximum information states for coherent scattering measurements
D. Bouchet, S. Rotter and A.P. Mosk, Nature Physics (2021)
https://www.nature.com/articles/s41567-020-01137-4