Volumetric displays are the 3D equivalent of holograms - more advanced solid volumetrics exist as well. They are very common in the Star Army universe.
Volumetric displays are three dimensional showing of a light field's image to create a graphic display. It is done by a scattering and emitting of light from a region in space. It reaches the eye directly from the source with no need for an intermediary object. Visually, they can be indistinguishable from an actual subject. The volumetric display shows perspective that changes realistically with a change in position of the observer.
Volumetrics, or holographs as they have once been called, are used in many places and have been for years upon years. Their construct has changed marginally and the resulting image and information production technology has received little change in the past years.
Lasers are emitted from a central space and pushed into the visual range of the user by way of atomization and create a visual to the unaided eye of observer. They work by creating a multiscopy that can be looked at from multiple angles. It captures and reproduces a light field for the viewer to recognize as the original subject without lacking detail or clarity. The laser diodes burst excited plasma in the air and incites oxygen and nitrogen molecules in the air. As Hard Light (Technology) is capable of doing, it replicates matter while having no mass itself.