SCExAO will be at SPIE (part 2)

Just like the title of the post says: part 2 of our massive submission of abstracts for the the next astronomy SPIE conference.

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Olivier submitted:

The Subaru Coronagraphic Extreme AO (SCExAO) system: Wavefront control and detection of exoplanets with coherent light modulation in the focal plane

The SCExAO system is designed to enable high contrast imaging at small angular separation (less than 0.5”) in the near-IR. It receives light from Subaru Telescope’s AO system and includes a second step of wavefront control and a high performance PIAA coronagraph. Light is then sent to the HiCIAO camera. For wavefront sensing, SCExAO uses a MEMS type deformable mirror to introduce known diversity in the pupil phase. The corresponding modulation is detected in the science focal plane, and leads to a measurement of the residual wavefront aberrations. The same modulation is also simultaneously used to differentiate residual scattered starlight (which is coherent with the light introduced in the focal plane by the modulation) from actual sources (planets, disks).

This combined wavefront control and coherent detection scheme is ideally suited for detection of faint companions at small angular separation. Detailed numerical simulations and recent laboratory results show that this techniques can calibrate and remove static and slow speckles which traditionally limit high contrast detections. A visible light lab prototype system at Subaru Telescope recently demonstrated speckle halo reduction to 2e-7 contrast within 2 lambda/D, and removal of static coherent speckles to 3e-9 contrast.

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Frantz submitted:

The Subaru Coronagraphic Extreme AO system: progress report

In 2009 our group started the integration of the SCExAO project, a highly flexible, open platform for high contrast imaging at the highest angular resolution, to be inserted between the coronagraphic imaging camera HiCIAO and the 188-actuator AO system of Subaru. In its first version, SCExAO combines a MEMS-based wavefront control system feeding a high performance PIAA-based coronagraph, that suppresses the central obscuration and the thick spider vanes while preserving throughput and angular resolution. It also includes a coronagraphic low-order wavefront sensor, a non-redundant aperture mask and a visible imaging mode, all of them designed to take full advantage of the angular resolution (40 mas in the H-band) that an 8-meter telescope has to offer.