Figure 16.6 — Light-driven micromachines Figure 16.6 — Light-driven micromachines. (a) Rendering of an optical microrotor with the integration of an optical fibre to supply the driving optical force. (b) Optical microrotor based on a vaterite particle (4 μm radius) set into rotation by transfer of spin angular momentum. The flow field (arrows) around the rotor is measured by multipoint holographic optical velocimetry. (c) Particles (800 nm diameter) trapped and rotated in holographic optical vortices. The resulting device operates as an optomechanical micropump. The white circles identify the trajectory of a single sphere as it moves through the pump 25 μm to the left in 7 s.Figure (a) is reproduced with permission from Metzger et al., J. Opt. 13, 044018. Copyright (2011) IOP Publishing. Reproduced by permission of IOP Publishing. All rights reserved.Figure (b) is reprinted figure from Di Leonardo et al., Phys. Rev. Lett. 96, 134502. Copyright (2006) by the American Physical Society.Figure (c) is reprinted from Ladavac and Grier, Opt. Express 12, 1144–9. Copyright (2004) The Optical Society.