Light-actuated contactiess macro motors exploiting Benard-Marangoni convection

Near-infrared light is commonly used to move small objects floating on water by exploiting the Benard-Marangoni convection. This is because infrared light is absorbed well by water and the induced thermal gradients arc responsible for the objects motion. However, visible light was recently used to move macroscopic objects on the free liquid surfaces. In this work, we show the use of visible light to rotate symmetric millimeter-sized objects. Those objects represent light-driven macro motors that are able to work in a continuous or step-by-step mode. We studied light intensity's effects on our system's angular velocity and estimated the entire process's conversion efficiency. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement