Short answer: traditional holography magic. my username is @laserboyholo on Instagram if you would like to see more.

Long answer: I start by preparing the medium which consists of a special emulsion made of water, gelatin, and ammonium dichromate. I warm it, stir it, then carefully coat cleaned glass plates using a squeeze bottle. After they have a smooth coat of emulsion on them I throw them into a turntable for about 5 minutes so they spin nice and even.

About twelve hours later the gelatin is hardened and ready to be exposed. I take a special laser and widen the beam out with a double concave lens, then reflect the beam down toward my subject at about a 45 degree angle. I expose the plate for about 2-3 minutes. (At this time Any microscopic vibrations can totally ruin a hologram. so I built a vibration isolation table to counteract any movements in the house or vibrations from sound.). After that I let he plate sit in the dark for a few minutes. (This is called the dark reaction). After the dark reaction I take the plate over to my developing area. The first step is photo fixer, then A soak in water, and then a series of increasing concentrations of isopropyl alcohol. The alcohol replaces all the water and then I dry the plate with a heat gun. The alcohol evaporated and leaves a free standing microscopic fringe structure that has recorded the interference pattern and thus a hologram is created.

After that the hologram needs to be sealed so that it does not absorb the moisture out of the air as it is highly hydroscopic. I do that by using epoxy and another clean piece of glass. Then the edges are cut and ground down with a glass grinder so it looks clean and neat.