Utsunomiya University of Japan has developed a prototype of a holographic display with a true three-dimensional image, in which the working object is not light, but a liquid. Let's face it - humanity needs not an abstract picture floating in the air, but a real, applied gadget. For example, a massive 360º screen filled with a transparent substance.
The liquid that Japanese scientists poured into the container has a certain viscosity index. If you shoot it from a laser with a femtosecond (one quadrillion second) pulse, a group of bubbles forms at the desired point. Due to the high viscosity of the medium, they do not float immediately, but slowly drift, forming a structure for displaying a voxel - a three-dimensional pixel, the main element of a hologram.
The bubbles themselves simulate a tiny screen onto which light must be projected to produce an image. They scatter it and the glowing voxel begins to visually stand out from the surrounding space. The rest is a matter of technology - you just need to increase the number of light sources and develop an algorithm for step-by-step generation and illumination of bubbles for "drawing" an arbitrary picture. And given the short lifespan of bubbles, it opens up prospects for interesting animation.
In a working prototype, the size of the holographic "little mermaid" is only a few millimeters, and the cost of maintaining complex lasers is alarmingly high. Expecting the technology to be implemented as a commercial retail product like a home monitor isn't even in the near future. However, scientists are optimistic that generous customers may be interested in their development. For example, exhibition centers, museums, universities or the military.