Frugal open-loop coherent wave control in metasurface-programmable complex media

Philipp del Hougne

doi:10.1117/12.3015810

10 June 2024 Frugal open-loop coherent wave control in metasurface-programmable complex media

Philipp del Hougne

Proceedings Volume 12990, Metamaterials XIV; 129900G (2024) https://doi.org/10.1117/12.3015810
Event: SPIE Photonics Europe, 2024, Strasbourg, France

Abstract

The control of wave scattering in unknown complex media (e.g., chaotic cavities) that can be reconfigured by a programmable metasurface is a seemingly daunting task: the mapping from metasurface configuration to scattering matrix is non-linear (due to non-locality), and there is no a priori knowledge of geometry or material composition of the unknown complex medium. Yet, this mapping must be known to enable open-loop wave control. Training a deep neural network to approximate the mapping is a potential solution. However, we show here that formulating a physical model is surprisingly simple and offers 10X advantages over the use of deep learning in terms of the achieved accuracy, the model compactness (number of model parameters) and the number of required calibration measurements. Surprisingly, the physical model can be trained based on phase-insensitive measurements which drastically alleviates the measurement complexity. This unlocks previously unimagined regimes of phaseless coherent wave control combining wavefront shaping and metasurface tuning, e.g., to tune a complex system to coherent perfect absorption (CPA) at a desired frequency and to identify the CPA wavefront without ever measuring phase. This remarkable phase-retrieval ability can be traced back to the mathematical structure of the physical model that imposes strong constraints on the possible model parameter values. The constraints are so strong that one can even estimate an entire scattering matrix (up to some sign ambiguities) by only inputting/outputting waves through a subset of the ports while tuning the loads terminating the remaining ports.

Conference Presentation

Citation Download Citation

Philipp del Hougne "Frugal open-loop coherent wave control in metasurface-programmable complex media", Proc. SPIE 12990, Metamaterials XIV, 129900G (10 June 2024); https://doi.org/10.1117/12.3015810

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available