Multi-Objective Tweezers in Scattering Media

TL;DR

This paper introduces a method to shape sound or light waves to manipulate multiple objects simultaneously within complex scattering media, achieving optimal forces and torques under competing objectives.

Contribution

It provides a theoretical framework for Pareto-optimal wave shaping to control multiple objects in scattering media, including bounds on achievable objectives.

Findings

Maximal achievable force or torque for a single object derived

Pareto-optimal actuation for multiple objects demonstrated

Exact bounds on incompatible objectives established

Abstract

Radiation forces and torques enable the manipulation of objects with acoustic and electromagnetic waves. Yet, harnessing them in complex scattering media remains a formidable challenge, especially when multiple objects must be controlled under competing objectives. Here, we demonstrate that sound or light can be shaped to tailor momentum transfer to multiple objects simultaneously in a complex scattering medium. For a single object, our theory yields the maximal achievable force or torque; for multiple objects, it produces Pareto-optimal actuation and exact bounds on the simultaneous realization of incompatible objectives. This opens new applications for wave tweezers, enabling selective and precise manipulation of objects within complex media, ranging from the handling of cells, organoids, or microrobots, to targeted drug delivery in biological media.