Universal Light-Driven Micro/Nanoscale Rotors

Abstract The capability of rotating micro/nanoscale particles and structures is important for micro/nanorobotics, three-dimensional particle imaging, and lab-on-a-chip systems. Light-driven rotors are especially attractive due to the fuel-free and remote operation. However, relying on a torque that arises from the momentum exchange with photons, current light-driven rotors require laser beams with designed intensity profile and polarization, or rotors with sophisticated shapes or material birefringence These requirements hinder the light-driven rotation of many highly symmetric or isotropic particles, including biological cells, with simple optics. Herein, we report a universal approach to the out-of-plane rotation of various objects, including spherically symmetric and isotropic particles, using single arbitrary low-power laser beams. Moreover, the driving laser beam is positioned away from the rotors to reduce optical damage from the direct light illumination. The working mechanism of the rotors based on opto-thermo-electrical coupling is elucidated by systematic experiments combined with multiscale simulations. With its general applicability and simple optics, our universal light-driven rotation platform will become an essential component in various scientific research and engineering applications.