TY - GEN
T1 - Experimental study of a low-order wavefront sensor for high-contrast coronagraphic imagers
T2 - Space Telescopes and Instrumentation 2014: Optical, Infrared, and Millimeter Wave
AU - Lozi, Julien
AU - Belikov, Ruslan
AU - Thomas, Sandrine J.
AU - Pluzhnik, Eugene
AU - Bendek, Eduardo
AU - Guyon, Olivier
AU - Schneider, Glenn
N1 - Publisher Copyright:
© 2014 SPIE.
PY - 2014
Y1 - 2014
N2 - For the technology development of the mission EXCEDE (EXoplanetary Circumstellar Environments and Disk Explorer) - a 0.7 m telescope equipped with a Phase-Induced Amplitude Apodization Coronagraph (PIAA- C) and a 2000-element MEMS deformable mirror, capable of raw contrasts of 10-6 at 1.2 λ/D and 10-7 above 2 λ /D - we developed two test benches simulating its key components, one in air, the other in vacuum. To achieve this level of contrast, one of the main goals is to remove low-order aberrations, using a Low-Order WaveFront Sensor (LOWFS). We tested this key component, together with the coronagraph and the wavefront control, in air at NASA Ames Research Center and in vacuum at Lockheed Martin. The LOWFS, controlling tip/tilt modes in real time at 1 kHz, allowed us to reduce the disturbances in air to 10-3 λ/D rms, letting us achieve a contrast of 2.8×10-7 between 1.2 and 2 λ/D. Tests are currently being performed to achieve the same or a better level of correction in vacuum. With those results, and by comparing them to simulations, we are able to deduce its performances on different coronagraphs - different sizes of telescopes, inner working angles, contrasts, etc. - and therefore study its contribution beyond EXCEDE.
AB - For the technology development of the mission EXCEDE (EXoplanetary Circumstellar Environments and Disk Explorer) - a 0.7 m telescope equipped with a Phase-Induced Amplitude Apodization Coronagraph (PIAA- C) and a 2000-element MEMS deformable mirror, capable of raw contrasts of 10-6 at 1.2 λ/D and 10-7 above 2 λ /D - we developed two test benches simulating its key components, one in air, the other in vacuum. To achieve this level of contrast, one of the main goals is to remove low-order aberrations, using a Low-Order WaveFront Sensor (LOWFS). We tested this key component, together with the coronagraph and the wavefront control, in air at NASA Ames Research Center and in vacuum at Lockheed Martin. The LOWFS, controlling tip/tilt modes in real time at 1 kHz, allowed us to reduce the disturbances in air to 10-3 λ/D rms, letting us achieve a contrast of 2.8×10-7 between 1.2 and 2 λ/D. Tests are currently being performed to achieve the same or a better level of correction in vacuum. With those results, and by comparing them to simulations, we are able to deduce its performances on different coronagraphs - different sizes of telescopes, inner working angles, contrasts, etc. - and therefore study its contribution beyond EXCEDE.
KW - Control
KW - Coronagraph
KW - EXCEDE
KW - High-contrast imaging
KW - Linear quadratic Gaussian controller
KW - Low-order wavefront sensor
KW - PIAA
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U2 - 10.1117/12.2056735
DO - 10.1117/12.2056735
M3 - Conference contribution
AN - SCOPUS:84927643807
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Space Telescopes and Instrumentation 2014
A2 - Oschmann, Jacobus M.
A2 - Clampin, Mark
A2 - MacEwen, Howard A.
A2 - Fazio, Giovanni G.
PB - SPIE
Y2 - 22 June 2014 through 27 June 2014
ER -