Abstract: In a general aspect, a structured optical beam with position-dependent polarizations is prepared for human observation. In some examples, an optics method includes processing an optical beam to produce a structured optical beam for human observation. Processing the optical beam includes receiving the optical beam from a laser source; attenuating the optical beam to an exposure irradiance level that is safe for direct viewing by a human eye; expanding the optical beam to a size configured for a field of view of the human eye; and preparing the optical beam with a position-dependent polarization profile. The structured optical beam, which has the position-dependent polarization profile, is directed towards an observation region for human observation.

Abstract: In a general aspect, a collimator system is described. In some aspects, a neutron beam collimation method includes receiving a neutron beam from a neutron source; polarizing the neutron beam using a polarizer, and obtaining a collimated neutron beam from the polarized neutron beam. The neutron beam generated by the neutron source has a first beam divergence and includes a plurality of neutrons. The collimated neutron beam has a second beam divergence that is less than the first beam divergence. Obtaining the collimated neutron beam includes mapping transverse momentum of each respective neutron, of the plurality of neutrons, onto a polarization degree of freedom of the respective neutron by applying a sequence of phase shift gradients to the polarized neutron beam, and after applying the sequence of phase shift gradients, passing the polarized neutron beam through an analyzer.

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, a structured optical beam with position-dependent polarizations is prepared for human observation. In some examples, an optics method includes processing an optical beam to produce a structured optical beam for human observation. Processing the optical beam includes receiving the optical beam from a laser source; attenuating the optical beam to an exposure irradiance level that is safe for direct viewing by a human eye; expanding the optical beam to a size configured for a field of view of the human eye; and preparing the optical beam with a position-dependent polarization profile. The structured optical beam, which has the position-dependent polarization profile, is directed towards an observation region for human observation.

Abstract: In a general aspect, a collimator system is described. In some aspects, a neutron beam collimation method includes receiving a neutron beam from a neutron source; polarizing the neutron beam using a polarizer, and obtaining a collimated neutron beam from the polarized neutron beam. The neutron beam generated by the neutron source has a first beam divergence and includes a plurality of neutrons. The collimated neutron beam has a second beam divergence that is less than the first beam divergence. Obtaining the collimated neutron beam includes mapping transverse momentum of each respective neutron, of the plurality of neutrons, onto a polarization degree of freedom of the respective neutron by applying a sequence of phase shift gradients to the polarized neutron beam, and after applying the sequence of phase shift gradients, passing the polarized neutron beam through an analyzer.

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.