title: Midinfrared broadband achromatic astronomical beam combiner for nulling interferometry.
abstract: Integrated optic beam combiners offer many advantages over conventional bulk optic implementations for astronomical imaging. To our knowledge, integrated optic beam combiners have only been demonstrated at operating wavelengths below 4 μm. Operation in the midinfrared wavelength region, however, is highly desirable. In this paper, a theoretical design technique based on three coupled waveguides is developed to achieve fully achromatic, broadband, polarization-insensitive, lossless beam combining. This design may make it possible to achieve the very deep broadband nulls needed for exoplanet searching.
authors.affiliation: Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Avenue, Ann Arbor, Michigan 48109, USA. hkhsiao@umich.edu
authors.forename: Hsien-kai
authors.initials: HK
authors.lastname: Hsiao
authors.forename: Kim A
authors.initials: KA
authors.lastname: Winick
authors.forename: John D
authors.initials: JD
authors.lastname: Monnier