Light-momentum-driven soft optical waveguide micro-actuators

Radiation pressure of light allows us to exert forces and trap microscopic objects by highly focused laser beams in the form of optical tweezers. In principle, light also exerts mechanical forces in curved optical waveguides as photons alter their direction and momentum. While these optical forces are typically negligible due to the rigidity of conventional materials, we demonstrate that soft photopolymer optical waveguides can undergo significant mechanical deformation driven by light momentum. Using two-photon polymerization direct laser writing, we fabricate micron-scale curved nanowire waveguides that exhibit large-scale movements when guiding light. An analytical optomechanical model accurately predicts the observed shape deformations and their power-dependent behavior. Our findings pave the way for the development of light-driven micro-actuators, offering fresh opportunities for photonic and microelectromechanical systems.