Light, Matter, Action: Shining Light on Active Matter

Light carries energy and momentum. It can therefore alter the motion of objects on the 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 properties, such as its wavelength, polarization, and momentum. We then argue that fully exploiting light with all of its properties will play a critical role in increasing 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 toward technological applications.

Automated summary

Light can alter the motion of objects and is an ideal tool to drive microscopic particles and make them active. Research in the field of soft active matter has focused on utilizing light intensity, but recent advances have also explored other properties of light such as wavelength, polarization, and momentum. Fully exploiting all properties of light will enhance control over active matter and the flow of light itself, leading to advancements in soft active matter systems and their technological applications.