Light angular momentum of a plane wave diffracted by a two-dimensional simple object.

Olivier Emile (1) , Morgane Le Meur (1) , Janine Emile (2)

1 URU 435 LPL - URU 435 Laboratoire de physique des lasers
2 IPR - Institut de Physique de Rennes

The question of the transfer of angular momentum from light to objects is a key issue in optical tweezers and thus raises issues in physics, chemistry, and biology. Most of the attempts have been performed either with spin angular momentum using light's polarization or using orbital angular momentum with twisted beams. We experimentally demonstrate here the exchange of angular momentum from a linearly polarized plane wave to a two dimensional asymmetric object. More precisely, we show that the diffracted light from a snail-shaped mask carries local orbital angular momentum whose topological charge depends on the symmetry of the object. This opens the way to a means to produce micrometer-sized twisted beams from a high power laser or even pulsed beams.

Domaines: Optique [physics.optics]

Olivier Emile, Morgane Le Meur, Janine Emile. Light angular momentum of a plane wave diffracted by a two-dimensional simple object.. Physical Review A : Atomic, molecular, and optical physics [1990-2015], 2014, 89 (1), pp.013846. ⟨10.1103/PhysRevA.89.013846⟩. ⟨hal-00993185⟩