Real and Fake Holograms

A question often comes to the Lab on the feasibility of creating a Star Wars-esq Hologram: whereby a volume of light is projected into thin air and can be seen from any angle. For all intents and purposes, this is not currently possible (emerging technology is listed below). Most of what we call holograms are reflections on glass or other materials , so that what appears is a floating, semi-transparent two dimensional image. This is a quick run-down of the various method’s available and our experiment with a Pepper’s Ghost box.

 
Holography

Actual Holograms are essentially recordings of the light field generated by an object onto a photographic plate. This allows a person to walk past the recorded image and see 3D object at different angles. This is a true 3D image as two people viewing it from different angles will be seeing the recorded object differently

 
Pepper’s Ghost

Most of what we are talking about when we talk about Holograms that are used theatrically or in products is an old theater trick called Pepper’s Ghost, where an image is reflected onto angled glass so that it appears to float in a real environment.
 

 
This is essentially the “Tupac” method, and is also used on a consumer level in products like the Holo Cube, which are really just a screen, a piece of glass angled at 45 degrees, and an enclosure.
 

 
While an interesting effect, the image itself is not holographic as it is still a flat floating image.

We decided to build our own test using an iPad, a 4-sided foam core box and a piece of plexiglass. Additionally, we added a parallax effect so that rotating the box will let you view the 3D model at different angles, simulating the behavior of a real hologram.

 
New and Emerging Technology

The ultimate goal is to create a volumetric projection anywhere in space. There are a few new offerings that build off of Pepper’s Ghost or other methods to try to get closer to that: A company called Looking Glass creates a volumetric display by projecting onto multiple layers of glass so that there is some feeling of volume when you move around the display. Another product in development is
Holovect which creates a grid of fine mist and projects a laser image onto it.

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