Optically induced rotation of micro-wheel gears fabricated from photopolymerizable liquid crystal

Liquid crystal (LC) molecules that carry photopolymerizable end groups absorb photon energy via a two-photon process and can thus be photofabricated. Some of the present authors reported that circularly polarized laser beams induced rotational motions of the photopolymerized LC micro-objects that had cylindrical shapes (K. Ito and M. Kimura, Jpn. J. App. Phys. 49 (2010) 040208). Here we first investigated the fabrication accuracy of the present LC molecules, and fabricated micro-wheel gears with different sizes. Furthermore, we have demonstrated that the rotational direction can be reversed with their rotational frequencies unchanged by switching from right-handed circularly polarized light to left-handed one.