title: Achromatic interfero-coronagraph with two common-path interferometers in tandem.
abstract: To attain deeper nulling for an extended incoherent star disk a scheme for an achromatic interfero-coronagraph, incorporating two common-path interferometers in tandem, is proposed. Analytical and numerical predictions of the performance, which are in reasonably good agreement, are presented. The predicted performance improvement, by using two interferometers in tandem, is demonstrated by a preliminary experiment. A star coronagraph based on the proposed technique has the possibility to reach a 10(-10) achromatic nulling contrast for an almost 10(-2) lambda/D effective source size.
authors.affiliation: National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan. alexander.tavrov@nao.ac.jp
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Tavrov
authors.forename: Jun
authors.initials: J
authors.lastname: Nishikawa
authors.forename: Motohide
authors.initials: M
authors.lastname: Tamura
authors.forename: Lyu
authors.initials: L
authors.lastname: Abe
authors.forename: Kaito
authors.initials: K
authors.lastname: Yokochi
authors.forename: Takashi
authors.initials: T
authors.lastname: Kurokawa
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Takeda