Etalon

An etalon is an optical device made of two highly reflective surfaces positioned parallel to each other. It functions as a high-precision filter or mirror, creating interference effects that allow only light of specific wavelengths to pass through or reflect back. This property makes etalons useful in applications like spectroscopy, lasers, and optical communication systems, where precise control of light wavelengths is essential. By adjusting the spacing between the surfaces, the device can be tuned to select or analyze particular wavelengths with great accuracy.