Optically induced rotation of anisotropic micro‐objects fabricated by surface micromachining

Optical trapping and directional high‐speed rotation by radiation pressure are demonstrated for anisotropic micro‐objects fabricated by reactive ion‐beam etching. These micro‐objects, which have shape dissymmetry (not bilateral symmetry but rotational symmetry) in the horizontal cross section, rotate about the laser beam axis in the designed direction in a liquid medium (e.g., water or alcohol). The rotation speed is almost proportional to the input laser power.