Current available 3D holographic displays are based on having a “screen”, surface or substance (such as dust or water vapor) to intersect and interfere with the laser beam.
Taking this fact into consideration, the Japanese company "Aerial Burton" has improved the holographic technology. They created a holographic display that operates without any screen, surface or substance. It projects a 3D image into mid-air, achieved by using a pulse laser that ionizes air molecules, creating a 3D image. As you can see in the video, the laser is able to display 3D images in real time shooting 1kHz infrared pulse laser into a 3D scanner which reflects and focuses the pulses of the laser to specific points in the air.
According to Aerial Burton, this display can be used to help people in emergency situations, for example, power outage, earthquake or flood. People will be able to find evacuation routes and emergency supplies with the signalisation projected by this device. However, the 3D image’s resolution is not yet impressive, but for basic guidance display is excellent.