Optical manipulation and tweezers

Radiation pressure exerted by light was a lifelong passion for Arthur Ashkin. He foresaw that light pressure could do useful work and invented the optical tweezers that can trap microscopic objects, from small ‘living things’ down to individual atoms.

Electromagnetic fields in light waves are mainly transverse to propagation direction but actually also have longitudinal components, which may give rise to unexpected optical phenomena involving the angular momentum of light, such as transverse spin and optical torques.