Optofluidic rotation mode transitions control in hexagonal gold nanoprisms

Abstract

While optical torque manipulation has been extensively studied in one-dimensional micro- and nano-scale particle systems, the dynamics of multi-dimensional torque coupling with opto-hydrodynamic interactions remains theoretically under explored. This study systematically investigates the three-dimensional rotational dynamics of hexagonal gold nanoprisms in spatially modulated optical fields with controlled fluidic environments. Through quantitative analysis of particle trajectories under varying optical modulation periods, we demonstrated that by adjusting the modulation period the particle motion can be controlled across three distinct rotation modes: nutation-dominated motion, multi-mode stochastic motion, and constrained planar rotation. Crucially, the range of periodic nutation angles exhibits a dependence on modulation period in constrained planar rotation, enabling precise mode control. The demonstrated multi-mode control paradigm advances nanoparticle manipulation techniques, particularly for developing orientation-programmable nanomotors and adaptive micro-fluidic systems.