Light, Matter, Action: Shining light on active matter

TL;DR

This paper reviews recent progress in controlling soft active matter using light, emphasizing the potential of exploiting all light properties to enhance actuation and enable advanced technological applications.

Contribution

It highlights recent advances in light-controlled active matter and advocates for fully utilizing light's properties to improve control and functionality.

Findings

Light intensity control of active matter

Initial use of light wavelength, polarization, and momentum

Potential for advanced control and applications

Abstract

Light carries energy and momentum. It can therefore alter the motion of objects from atomic to astronomical scales. Being widely available, readily controllable and broadly biocompatible, light is also an ideal tool to propel microscopic particles, drive them out of thermodynamic equilibrium and make them active. Thus, light-driven particles have become a recent focus of research in the field of soft active matter. In this perspective, we discuss recent advances in the control of soft active matter with light, which has mainly been achieved using light intensity. We also highlight some first attempts to utilize light's additional degrees of freedom, such as its wavelength, polarization, and momentum. We then argue that fully exploiting light with all of its properties will play a critical role to increase the level of control over the actuation of active matter as well as the flow of light itself through it. This enabling step will advance the design of soft active matter systems, their functionalities and their transfer towards technological applications.