Why do we use white light for interferometry?

Usually for interferometry we use very narrowband light. A laser is a convenient source. However, it is possible with a lot of patience to get interference with broadband (white) light. I have done dozens of interferometers, and I only did white light once. I did get fringes but it was too difficult to get meaningful data. read more

A white light interferometer, used e.g. in the context of low-coherence interferometry, is an interferometer, typically a Michelson interferometer, which works with a white light source, i.e. with a light source with broad optical bandwidth. read more

Above: White light Interferogram, Below: Red-, Green- and Blue channels of the White light interferogram shown above As described here, white light interferometry is a non-contact optical method for surface height measurement on 3-D structures with surface profiles varying between tens of nanometers and a few centimeters. read more