between two points is the path that has the minimum OPL.

Optical path difference

The optical path difference (OPD) is the difference between the optical path lengths of two rays or beams reaching a common point. For monochromatic light, the OPD determines the corresponding phase difference through
:where is the vacuum angular wavenumber. For example, over the same geometric distance, light traveling in glass has a larger optical path

1.Previous
3.Next