Holograms

[makinsonc]

How do you make a hologram ?

[Clanad]

Check here:

http://van.hep.uiuc.edu/van/qa/section/Light_and_Sound/Lasers/909777795.htm

[Buenchico]

Basically, you need to fire laser light towards an object but split off part of the light en route. This light is reflected by a mirror to arrive at the same photographic film which also receives light reflected from the object. Interfence occurs between the two beams resulting in a 'diffraction grating' being created on the film surface.

Getting confused? There's plenty more information here but, unless you're familiar with the optical theories which occur in A-level physics, it's difficult to follow:
http://en.wikipedia.org/wiki/Hologram

Chris