High Contrast Imaging with Focal Plane Wavefront Sensing and PIAA for Subaru Telescopes Olivier Guyon Basile Gallet Eugene Pluzhnik Hideki Takami Shinichiro Takana Subaru Telescope / National Astronomical Observatory of Japan Motohide Tamura Lyu Abe National Astronomical Observatory of Japan Subaru AO team & HiCIAO team

Introduction / Outline Goal: high contrast at low inner working angle (IWA) Half the IWA = 8x more accessible planets 0.1'' – 0.2'' has 7x more planets than >0.2'' lots of science possible with ~1k actuators Reflected light from closeby planets is stronger at ~0.1''-0.2'', 1e8 contrast for some RV planets

High-contrast AO at Subaru Telescope AO elements curvature system (first light: end 2006) HiCIAO differential imaging near-IR camera (2007) ''Tweeter'' + low IWA coronagraph Nasmyth focus flexible & friendly environment PIAA

PIAA / APLC Hybrid coronagraph Angular separation Useful Throughput

Why focal plane wavefront sensing ? ''What you see is exactly what you want to remove'' Main sources of wavefront errors : - Photon noise - Time lag - Fitting errors # of elements Aliasing - Non-common path errors optical components (static) actuator vs. WFS registration (static & dynamic) - scintillation - wavefront chromaticity refraction index of air (OPD chromaticity) Fresnel propagation (OPD and ampl. Chromaticity) chromatic shear of wavefront

''fundamental'' contrast limitations of AO with vis. WFS & near-IR imaging 8m telesc. V WFS H imaging (Guyon, 2005)

Wavefront sensors ''efficiencies'' (Guyon 2005) Square root of # of photons required to reach fixed sensing accuracy plotted here for phase aberrations only.

''Dark Hole'' DM control If wavefront is known, DM can be controlled to ''perfectly'' cancel speckles JPL High contrast imaging testbed Malbet, Yu & Shao (1995) Guyon (2005) Give'on ( ) Borde & Traub (2006)

Fast(er) algorithm using linear approximations – few ms on single CPU, code not optimized for speed

PIAA coronagraph development at Subaru co-funded by JPL and Subaru/NAOJ Utilizes lossless beam apodization with aspheric optics (mirrors or lenses) to concentrate starlight is single diffraction peak (no Airy rings). - high contrast - Nearly 100% throughput - IWA < 2 l/d - 100% search area - no loss in angular resol. - can remove central obsc. and spiders - achromatic (with mirrors) For Subaru, Lyot Coronagraph with PIAA- apodized input pupil. IWA ~ 1 lambda/d

Early demonstration in lab (Galicher et al. 2005) Lenses made by Masashi Otsubo (ATC, NAOJ)

PIAA mirror units (Axsys) JPL-funded TPF-C technology development

32x32 MEMs DM is used for FPAO test in lab with PIAA coronagraph One of 14 boards to drive the MEMs DM. 80 channels/board 16 bit resolution slow & fast interface (> kHz update) S. Colley AO electronic eng. Subaru Telescope

Closed loop WFC Without prior knowledge, 3 frames sufficient for WF measurement

Low Order Wavefront Sensor (LOWFS) LOWFS performance Small (<<lambda) wavefront error produces large flux changes in the LOWFS images