title: Interferometric nulling of four channels with integrated optics.
abstract: Nulling interferometry has been identified as a competitive technique for the detection of extrasolar planets. In its basic form, the technique consists of combining out-of-phase a single pair of telescopes to effectively null the light of a bright star and reveal the dim glow of the companion. However, in order to mitigate the effect of the stellar leaks through the interferometer, a broad angular central null is required. The hierarchical combination of several pairs of telescopes can accomplish this task. We have manufactured and tested with monochromatic light an integrated optics component, which combines a linear array of four telescopes in the nulling mode envisaged by Angel and Woolf [Astroph. J.475, 373-379 (1997).10.1086/apj.1997.475.issue-1ASJOAB0004-637X]. By simulating in the laboratory the motion of a star in the sky, we could measure the expected angular transmission of the four-telescope nuller. Moreover, the tests have demonstrated a broad nulling scaling as the fourth power of the baseline delay.
authors.forename: Ronny
authors.initials: R
authors.lastname: Errmann
authors.forename: Stefano
authors.initials: S
authors.lastname: Minardi
authors.forename: Lucas
authors.initials: L
authors.lastname: Labadie
authors.forename: Balaji
authors.initials: B
authors.lastname: Muthusubramanian
authors.forename: Felix
authors.initials: F
authors.lastname: Dreisow
authors.forename: Stefan
authors.initials: S
authors.lastname: Nolte
authors.forename: Thomas
authors.initials: T
authors.lastname: Pertsch