Rotational control of anisotropic micro-objects by optical pressure

Micro-objects having an anisotropic geometry-not bilateral symmetry but rotational symmetry in the horizontal cross section-were fabricated by reactive ion-beam etching (RIBE) of a 10-/spl mu/m-thick silicon dioxide layer. These artificial micro-objects, suspended in liquid and irradiated by a strongly focused laser beam, rotated about the laser beam axis in the expected direction and the speed of rotation is proportional to the input laser power.