For one of my (many) science-fiction projects, I am designing immense rotating space-habitats. These titanic structures, (similar to Bishop rings; see here https://en.wikipedia.org/wiki/Bishop_Ring_(habitat) have an area comparable to that of Germany, and are large enough to retain an atmosphere, with just high walls that prevent the air from spilling out into space.
However, awesome as these things are, they need a source of illumination. My first thought was some kind of mirror arrangement, but I kind of want there to be something visible as a sun in the habitat’s “sky”, so I came up with another idea. If there were some kind of projectors on the walls of the habitat, they could project the holographic image of a sun, which would provide both lighting and something nice to look at. I thought that, rather than use an electricity-powered laser, these projectors have a lens that focuses light from the actual sun (which the habitat orbits) into a beam that is then used to generate the hologram.
But reality check: would this work? I am no expert on holography and am kind of expecting there to be a problem with this system, but I want to be sure. So, to recap, is there a way to create a holographic projector which uses a focused beam if sunlight instead of a laser, and therefore can operate whenever sunlight happens to fall on it?