A feedback-controlled optoelectronic platform for programming interactions in active matter

Active matter systems involve complex interactions between constituent particles, often mediated by physical or chemical fields, and in some cases, governed by sensing or decision-making processes. Experimentally controlling such interactions remains highly challenging, posing a major obstacle to systematic investigation. In this work, we present an optoelectronic tweezer (OET) platform that uses closed-loop feedback to program both motion and interactions in colloidal systems by dynamically patterning local electric fields with light. Operating at very low optical intensities, this approach allows rapid and precise control over dielectrophoretic forces acting on colloidal particles. We demonstrate the capabilities of this platform through the experimental realization of both a programmable active Brownian particle system and a communicating active particle system. This versatile platform bridges theoretical models of active matter and their experimental realization, enabling direct control over propulsion and interaction rules.