Ultra-High Resolution Spectrometers
Fabry-Pérot interferometers are optical resonators used for high-resolution spectroscopy. They use the phenomenon of multiple-beam interference that results when light shines through a cavity bounded by two reflective parallel surfaces. When the light hits one of the surfaces, some is transmitted out, and the remaining part is reflected back. Fabry-Pérot produces a circular fringe pattern, similar to the Michelson pattern. However, the fringes are thinning, brighter, and more widely spaced. As a result, these instruments are able to detect and resolve the fine features of a transmission spectrum with high precision.