Abstract: In a general aspect, optical beams are manipulated. In some cases, an optical device includes an inlet to receive a first beam, and one or more prism pairs. Each prism pair includes one or more birefringent gradients configured to transform the first beam into a second beam. The second beam is associated with a lattice of cells, where each cell includes a first portion and a second portion. The first portion is associated with a first orbital angular momentum (OAM) mode and a first polarization, and the second portion is associated with a second OAM mode and a second polarization.

Abstract: In a general aspect, the spin angular momentum of a neutron wave packet is coupled with the orbital angular momentum of the neutron wave packet. In some instances, an initial state of a neutron wave packet is generated. The neutron wave packet in the initial state has a spin angular momentum that is polarized in an axial direction. The neutron wave packet is directed through a quadrupole magnetic field that couples the spin angular momentum of the neutron wave packet with an orbital angular momentum of the neutron wave packet. A spin-orbit state of the neutron wave packet is produced from the quadrupole magnetic field.