Halftoning for high-contrast imaging
1 European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany
2 Aktiwave, 241 Ashley drive, Rochester, NY, 14620, USA; LESIA, Observatoire de Paris Meudon, 5 pl. J. Janssen, 92195 Meudon, France
3 LAM, Laboratoire d’Astrophysique de Marseille, 38 rue Frédéric Joliot Curie, 13388 Marseille Cedex 13, France
a e-mail: email@example.com
High-contrast instruments, such as SPHERE (upcoming planet finder instrument for the ESO-VLT), or EPICS (planet hunter project for the future E-ELT), will require customized components with spatially varying transmission (e.g. coronagraphs, optical components that reduce the contrast between a companion and its parent star). The goal of these sub-systems is to control the spatial transmission, either in a pupil plane (pupil apodization), or in a focal plane of the instrument (occulting mask, i.e. low-frequency filter). Reliably producing components with spatially varying transmission is not trivial, and different techniques have been already investigated for application to astronomy (e.g. metal deposition with spatially-varying thickness, or high-energy beam sensitive glass using e-beam lithography). We present some results related to the recent development of components with spatially varying transmission using a relatively simple technique analogous to the digital halftoning process used for printing applications.
© Owned by the authors, published by EDP Sciences, 2011