How to make the electronic screen projected in the air in the photo?

We can often see a three-dimensional holographic communication technology in science fiction movies, which can project distant people or things into the air in three dimensions, just like the scene in the movie Star Wars. Holographic projection technology is the reverse display of holographic technology, which essentially forms a three-dimensional image on air or a special three-dimensional lens. Unlike plane projection, which only realizes stereoscopic effect on two-dimensional surface through perspective and shadow, holographic projection technology is a real 3D image. The first step is to record the light wave information of the object by using the interference principle, that is, the shooting process, and the second step is to reproduce the light wave information of the object by using the diffraction principle. At present, the whole system projection technology is divided into the following three types: 1. In Massachusetts, Chad Dyne, a 29-year-old science and engineering graduate, invented an air projection and interactive technology, which is a milestone in display technology. It can project an interactive image on the wall formed by airflow. This technology comes from the phantom principle. Projecting an image on water vapor can form an image with strong layering and three-dimensional sense due to uneven molecular vibration. Japanese technology company invented a 3D image that can be projected by laser beam. This technology uses nitrogen and oxygen to diffuse in the air, and the mixed gas becomes hot slurry, forming a short 3D image in the air. This method is mainly realized by a small explosion in the air. 3. Researchers from the Institute of Innovation and Technology of the University of Southern California announced that they have successfully developed a 360-degree holographic display screen. This technology projects an image on a high-speed rotating mirror to realize a three-dimensional image, but it seems a bit dangerous.