Contrast analysis and stability on the ExAO testbed

Conference · Tue Jun 10 04:00:00 EDT 2008

DOI:https://doi.org/10.1117/12.789452· OSTI ID:945515

Evans, J; Thomas, S; Gavel, D; Dillon, D; Macintosh, B

High-contrast adaptive optics systems, such as those needed to image extrasolar planets, are known to require excellent wavefront control and diffraction suppression. The Laboratory for Adaptive Optics at UC Santa Cruz is investigating limits to high-contrast imaging in support of the Gemini Planet Imager. Previous contrast measurements were made with a simple single-opening prolate spheroid shaped pupil that produced a limited region of high-contrast, particularly when wavefront errors were corrected with the 1024-actuator Boston Micromachines MEMS deformable mirror currently in use on the testbed. A more sophisticated shaped pupil is now being used that has a much larger region of interest facilitating a better understanding of high-contrast measurements. In particular we examine the effect of heat sources in the testbed on PSF stability. We find that rms image motion scales as 0.02 {lambda}/D per watt when the heat source is near the pupil plane. As a result heat sources of greater than 5 watts should be avoided near pupil planes for GPI. The safest place to introduce heat is near a focal plane. Heat also can effect the standard deviation of the high-contrast region but in the final instrument other sources of error should be more significant.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA
• Sponsoring Organization: USDOE
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 945515
• Report Number(s): LLNL-PROC-404640
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
99 GENERAL AND MISCELLANEOUS
DIFFRACTION
HEAT SOURCES
MIRRORS
OPTICS
PLANETS
SPHEROIDS
STABILITY
TELESCOPES