Liquid crystalline polymers are attractive materials for untethered miniature soft robots. When they contain azo dyes, they acquire light-responsive actuation properties. However, the manipulation of such photoresponsive polymers at the micrometer scale remains largely unexplored. Here, we report uni-and bidirectional rotation and speed control of polymerized azo-containing chiral liquid crystalline photonic microparticles powered by light. We first study the rotation of these polymer particles in an optical trap experimentally and theoretically. The micro-sized polymer particles respond to the handedness of a circularly polarized trapping laser due to their chirality and exhibit uni-and bidirectional rotation depending on their alignment within the optical tweezers. The attained optical torque causes the particles to spin with a rotation rate of several hertz. The angular speed can be controlled by small structural changes, induced by UV light absorption. After switching off the UV illumination, the particle recovers its rotation speed. Our results provide evidence of uni-and bidirectional motion and speed control in light-responsive polymer particles and offer a new way to devise light-controlled rotary microengines at the micrometer scale.Received: ((will be filled in by the editorial staff))Revised: ((will be filled in by the editorial staff))
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