An optical spin micromotor

2019-11-09 01:07:21

optical bead laser spin micromotor

责任者: Zong-Ping Luo;Yu-Long Sun;Kai-Nan An 单位: Biomech. Lab., Mayo Clinic, Rochester, MN, USA 来源出处: Applied Physics Letters(Appl. Phys. Lett. (USA)),2000/03/27,76(13):1779-81 摘要: An optical spin micromotor operated by optical tweezers, described in the present study, converts radiant energy directly to mechanical energy. This conversion is of great practical and fundamental interest. The optical spin micromotor consists of a two-bead linkage. The large bead (2.0 μm in diameter) is trapped by the optical tweezers and rotates around the laser beam axis. The small bead (0.94 μm in diameter) is partially coated with gold/palladium for generating the spin torque through the change of momentum from gradient radiation pressure of the same laser applied on the coated small bead. With a laser power of 29 mW at the sample plane, the spin speed averaged 158.8±155.5 rpm (mean±standard deviation) and the torque was estimated as 101.9±99.8 pN nm. This optical spin micromotor will be useful in (1) providing a fundamental step toward developing optical-operated mechanical devices, (2) twisting macromolecules, and (3) generating vortex and shear force in medium at nanoscale 关键词: micromotors;radiation pressure;optical spin micromotor;optical tweezers;two-bead linkage;laser beam;gold/palladium coating;torque;mechanical device;radiation pressure;Au-Pd