Spectral lines attenuating device for use in e.g. terrestrial object, observation apparatus, has core blade and mirrors forming Fabry Perot filter whose reflection spectrum has notches, where blade is formed by space separating mirrors

摘要

The device has a transparent core blade (22) forming two parallel main surfaces (24, 25), and a stack (26) of thin layers (28, 29) of dielectric materials of different refraction indexes extending against each of the surfaces. The thin layers are arranged for forming a mirror on each of the surfaces, where the mirrors present identical performance. The blade and the mirrors form a Fabry Perot filter whose reflection spectrum includes notches. The blade is formed by a space separating the mirrors, where the space is empty or filled with gas.