All existing commercial holographic technologies are essentially optical illusions. These are either 2D models that you need to look at from a certain angle, or templates for use with augmented reality glasses like HoloLens. True holograms, where light forms a three-dimensional image, are currently tiny and unsightly.
One of the reasons for this state of affairs is that when moving from a two-dimensional image to a three-dimensional image, the amount of data for recording this information grows to obscenely high rates. Processing such a digital array is an extremely laborious undertaking, therefore a 1 cubic centimeter hologram with a maximum viewing angle of only 3 degrees is considered a very worthy result. To create something bigger is elementary unprofitable.
While supercomputers don't fit in your pocket yet, scientists from the Korea Advanced Institute of Technology (KAIST) have proposed an intermediate option. They placed a pair of holographic diffusers between the light wave modulator and the viewer. These devices scatter light and create a kind of reflection, a copy of the original holographic image. It is full of noises and does not differ in detail, but it is much larger than the original, plus the viewing angle of the object increases.
Korean holographic technology diagram
In the experimental setup, the Koreans received a truly three-dimensional hologram 2 cm across, which can be observed at an angle of up to 35 degrees. In terms of the set of parameters, this is 2, 6 thousand times more efficient than the operation of existing holographic displays without diffusers. Controlling stray light turns it from an annoying hindrance into a useful ally, and in the long term this will allow the creation of large 3D screens. Convenient already for real work, and not just for laboratory experiments.