Essay Archive - Holograms
Holograms
Toss a pebble in a pond -see the ripples? Now drop two pebbles close
together. Look at what happens when the two sets of waves combine -you get
a new wave! When a crest and a trough meet, they cancel out and the water
goes flat. When two crests meet, they produce one, bigger crest. When two
troughs collide, they make a single, deeper trough. Believe it or not,
you've just found a key to understanding how a hologram works. But what
do waves in a pond have to do with those amazing three- dimensional
pictures? How do waves make a hologram look like the real thing?
It all starts with light....
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