Apparatus for and a method of rotating microscopic objects uses a beam of electromagnetic radiation. A microscopic, non-circularly symmetric distribution of electro-magnetic radiation is projected on to a region containing an object to be rotated so as to cause photons in the beam to refract around the objects. Rotating means then rotate that distribution and so rotate the objects. The distribution may be formed on the interference pattern between a beam having a Laguerre-Gaussian wave fronts and either a plane wave or a further Laguerre-Gaussian beam of opposite helicity.