https://phys.org/news/2018-01-holograms-d-thin-air.html
Scientists have figured out how to manipulate nearly unseen specks in the air and use them to create 3-D images that are more realistic and clearer than holograms, according to a study in Wednesday's journal Nature . The study's lead author, Daniel Smalley, said the new technology is "printing something in space, just erasing it very quickly."