Status of the LESIA High Contrast Bench development in the framework of the E-ELT

LESIA, Observatoire de Paris-Meudon, CNRS and University Denis Diderot Paris 7, 5 place Jules Janssen, 92195 Meudon, France

^a e-mail: marion.mas@obspm.fr

Abstract

In the framework of the instrument Exo-Planet Imaging and Spectrograph (EPICS), an optical bench is being set up in the Laboratoire d’Etudes Spatiales et d’Instrumentation en Astrophysique (LESIA). With this bench, we will test a new high contrast technique, the Self-Coherent Camera (SCC). As already described in Galicher et al. (2008), the SCC is able to measure the incoming phase defects and, in the same time, detect a faint companion in the residual speckle field. To reach high contrast detection, both coronagraphy and adaptive optics are used to make measurements with the SCC. The principle of the instrument is based on interferences between two beams. One of them is spatially filtered using a pinhole which filters the high frequencies of the star beam and stops the light from the companion. The recombination of these two beams takes place at the pupil plane in a Fizeau type setup. As a result, the speckles in the final focal plane created by residual aberrations will be encoded with fringes. To test this instrument in laboratory environment, we are developing a test bench which will combine high performance coronagraph (four-quadrant phase mask coronagraph), an extreme adaptive optics (a Boston electrostatic deformable mirror with 32x32 actuators) and the SCC itself. After introducing the principle of the SCC, we show the first results of a numerical study. We eventually describe the status of the test bench development.