"Ballistic" waves among chemically oscillating micromotors

Coordinating a group of chemically powered micromotors holds great importance in potential applications that involve a large population in a complex environment, yet information transmission at a population scale remains challenging. To this end, we demonstrate how propagating waves emerge among a population of spontaneously oscillating micromotors that dash toward a direction prescribed by their Janus orientations (termed a "ballistic" wave). Moreover, chemical communication among these micromotors enables the tuning of the speed and frequency of individual micromotors and their waves, by varying the population density or the viscosity of the medium. Motion waves propagating in one direction emerge from a population of chemically oscillating micromotors. Active motors on the wavefront move in random directions leading to a "ballistic" type wave.