Another version is the Fabry- Pérot type, in which monochromatic light is passed through a pair of parallel half-silvered glass plates producing circular interference fringes.
Of the several varieties of this device, the echelon consists of a stack of glass plates arranged stepwise with a constant offset and is used in spectroscopy to study hyperfine line structure. Another version is the Fabry- Pérot type, in which monochromatic light is passed through a pair of parallel half-silvered glass plates producing circular interference fringes. However, its most famous use can probably be attributed to the debunking of ether in the 1887 Michelson-Morley experiment. FTP, identify this type of device used to measure wavelengths and distances by producing interference fringes.
Of the several varieties of this device, the echelon consists of a stack of glass plates arranged stepwise with a constant offset and is used in spectroscopy to study hyperfine line structure.
{interferometer}