Laser has become a powerful tool to manipulate micro-particles and atoms by radiation pressure or photophoretic force,but its effectiveness for large objects is less noticeable.Here,we report the direct observation of...Laser has become a powerful tool to manipulate micro-particles and atoms by radiation pressure or photophoretic force,but its effectiveness for large objects is less noticeable.Here,we report the direct observation of unusual light-induced attractive forces that allow manipulating centimeter-sized curved absorbing objects by a light beam.This force is attributed to the radiometric effect caused by the curvature of the vane and its magnitude and temporal responses are directly measured with a pendulum.Simulations suggest that the force arises from the bending of the vane,which results in a temperature difference of gas molecules between the concave and convex sides due to unbalanced gas convection.This large force(~4.4μN)is sufficient to rotate a motor with four curved vanes at speeds up to 600 r/min and even lifting a large vane.Manipulating macroscopic objects by light could have significant applications for solar radiationpowered near-space propulsion systems and for understanding the mechanisms of negative photophoretic forces.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.61775036)the high-level talents program of Dongguan University of Technology(Grant No.KCYCXPT2017003).
文摘Laser has become a powerful tool to manipulate micro-particles and atoms by radiation pressure or photophoretic force,but its effectiveness for large objects is less noticeable.Here,we report the direct observation of unusual light-induced attractive forces that allow manipulating centimeter-sized curved absorbing objects by a light beam.This force is attributed to the radiometric effect caused by the curvature of the vane and its magnitude and temporal responses are directly measured with a pendulum.Simulations suggest that the force arises from the bending of the vane,which results in a temperature difference of gas molecules between the concave and convex sides due to unbalanced gas convection.This large force(~4.4μN)is sufficient to rotate a motor with four curved vanes at speeds up to 600 r/min and even lifting a large vane.Manipulating macroscopic objects by light could have significant applications for solar radiationpowered near-space propulsion systems and for understanding the mechanisms of negative photophoretic forces.
