How are holograms possible?

let me show you something I find completely magical behind this piece of glass there appears to be a three-dimensional scene you can move around your head and you see the light play off of the objects in different ways for example that glass Klein bottle in the front warps what's behind it but it's an illusion in reality all that's there is an empty table and a diverging laser beam shining on the glass inside that glass is a single piece of film that's been exposed in a very special way that records the entire threedimensional scene it's hard to capture in a video how surreal this feels in person because despite there being nothing behind that glass every visual cue available is screaming to your brain that something really is there one of my favorite versions of this is a recording taken of a microscope again it gives this illusion of a three-dimensional object stored on a two-dimensional piece of film and it's a little tricky to get this right but if you put your eye at just the right point in space you can look down the barel of the microscope and see what it's Imaging in this case a little microchip I want you to take a moment to reflect on just how incredible this is simply from the standpoint of how much information needs to be stored on that film an ordinary photograph records a scene from just a single viewing angle but right here we have available to us an entire Continuum of differing perspectives in the first example this includes how the light from the pie creature refracts through the glass in different ways from different angles or how sometimes you get this little glint of light off the disco ball every Optical detail from all these viewing angles is stored on that two-dimensional piece of film what you're looking at is a hologram when most people hear the word hologram what pops into their mind is something like what R2-D2 projects in Star Wars but real world Holograms are a special kind of recording taken on film that gives the illusion of looking through a window into a recorded scene the principle behind this was discovered by Dennis Gabor in 1947 while he was working on methods for electron microscopy and as The Story Goes the fundamental Insight came to him while ...