A term often used and just as often misunderstood, it traces its origin to Denis Gabor, inventor of holography and recipient of the Nobel Prize in Physics in 1971 for the invention of holography.
A hologram is a piece of film on which the full field of light has been recorded. There are a few ways to achieve this, but generally the method to produce a hologram is to make an interference pattern on the film using a laser with some of its light that is bounced off an object and some that hits the film directly. When suitably lit, the hologram perfectly reproduces the light field: one can move and look around the object as if the object was there.
If one were to cut the hologram in a half, one would be able to view the full image from both pieces of film! It would be like looking through half of a window rather than a full window.
OSU has a unique lab for holography, one of the few in the world, and offers several courses in it, all taught by Dr. Kagan.
It took many, many lab hours to get some results, as there are very specific processes must be followed. For example, when shooting an hologram, the exposure can last up to 20 or 40 seconds, and in that time, the object that is being exposed cannot move for more than a fraction of the wavelength of light, or else the diffraction pattern is ruined and the hologram won’t turn out. I got to work with lasers, optics, and a dark room to produce these.
Here are some, and unfortunately they are not as nice as seen in real life, since normal 2D imagining can’t reproduce the effects of the holograms.
These are videos, which look better, but below are some gifs, and remember, these aren’t boxes with objects in them, they are just 2D pieces of films, like photographs!