TECH + knowledge + Y: What is a hologram?

TECH + knowledge + Y: What is a hologram?


When we take a
photograph of an apple, the camera records the light
that bounced off the apple and went into the camera’s lens. But this only records a single
perspective of the apple. That’s why
photographs look flat. If we want to do a
little bit better, we could take two photographs
next to each other and then send one
of those images to one of your eyes and the
other image to the other eye. This is how 3D movies work,
and it gives them depth. But it still has a problem. You can’t turn your head and get
more perspectives on the apple. We can do better than this. Light is a wave. It’s like a water wave, only
water waves are made of water, and light waves are made of
electric and magnetic fields. We can deflect a light
wave by passing it through a diffraction grating. The finer the grating, the more
the light wave is deflected. And we can combine a bunch
of these diffraction gratings in order to shape a
light wave however we want it to be shaped. That’s exactly
what a hologram is. It’s a combination,
a superposition, of diffraction gratings
that are designed to reconstruct the original
light wave that bounced off of the apple. But how do we make
this hologram? Well, the way to
make the hologram is to take the light that’s
bouncing off the apple and mix it with a laser beam. Then they’ll form an
interference pattern, similar to when you drop
two pebbles into a pond. The waves spread out and meet. When they meet each
other, they form sort of a crosshatch pattern. We’re going to take
this crosshatch pattern, this light interference
pattern, and we’re going to put it in some
photographic chemicals that will record it. That’s how we make the hologram. Common examples of holograms
include credit card security images and novelty items. But the word hologram
is commonly misused to describe other things,
such as lenticular images and Pepper’s ghost. There’s a lot of exciting
research done in holograms. A really tricky but cool problem
is to make a moving hologram. That would be useful for
displays like TVs and computer displays. It could also be
useful for medicine. If, for example,
the doctor would be able to see a moving,
3D image of your heart, it would help him
or her diagnose you. Someday, we may even be
able to tell Obi-Wan Kenobi that he’s our only hope.

5 thoughts to “TECH + knowledge + Y: What is a hologram?”

  1. Georgia Tech for such a fascinating topic the video was so lacking. Unlike most people I at least know something about Holograms but if I didn't this video really tells me nothing that would give me a better understanding of what it is, how it is formed and why it does what it does.

  2. When it comes to use cases.. Hallolence and AR works much Better I guess. Presently holograms are only applicable in maas communication where people can afford to have ar glasses..

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