The Calculus of Holography
A Simplified Analysis of Holography
Assume a photographic plate in the xy plane:
Given a reference beam:
The reflected object beam is:
At the plate the fringe amplitude is given by:
because the square of the magnitude of a complex number is product with its complex conjugate.
where and is the zero order beam (it passes straight through the hologram). is the intensity of the reference beam and is the virtual image. The third term, , is the real image. It is important to notice that its amplitude is the complex conjugate of . (We have to flip the plate to make the conjugate or real image.)