Optical path difference

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created: 2021-11-30 01:51:06
modified: 2022-01-10 04:13:04

A difference in OPL between two paths is often called the optical path difference (OPD). This is important when trying to determine the phase difference for describing interference and diffraction.

And the phase difference from this:

Where is the wavelength in vacuum.

From the phase difference, we can determine what kind of interference occurs at the ends of the paths: constructive or destructive.