Abstract

In the field of imaging optical systems, anti-reflective (AR) coatings are widely used in order to reduce unwanted reflections. The LETI-CMO laboratory is involved in the development of an advanced spectral separator for earth observation [1] which uses absorbing diaphragms for the separation of the different optical paths. The optical specifications of such a sytem are drastic since a reflection lower than 2% and a transmission lower than 10^-3 are required on a spectral range as wide as 450 to 950 nm. In order to meet such specifications, we have chosen to develop an absorbing AR coating based on a new multilayer structure which uses thin metallic absorbing layers. As we will see, such structures exhibit particularly efficient absorbing properties.

© 1998 Optical Society of America