In the search for extra-solar Earth-like planets, nulling interferometry is required. This technique provides the extinction of the light from the parent star so as to "see" objects in its immediate vicinity. This nulling process is based on appropriate phase shifts applied to the collected waves made to destructively interfere. These phase shifts must be performed in the thermal infrared domain and must be achromatic so as to enable working on a large bandwidth. After briefly recalling the principle of nulling interferometry, we state what should mean "achromatic" in the context and we present various techniques potentially able to meet the stated requirements. Critical points and interesting features of the presented techniques are outlined.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.