The LBTI Fizeau imager – II. Sensitivity of the PSF and the MTF to adaptive optics errors and to piston errors
Hinz, P. M.
Hill, J. M.
AffiliationUniv Arizona, Steward Observ
Keywordsinstrumentation: adaptive optics
techniques: high angular resolution
MetadataShow full item record
PublisherOXFORD UNIV PRESS
CitationThe LBTI Fizeau imager – II. Sensitivity of the PSF and the MTF to adaptive optics errors and to piston errors 2017, 472 (3):3288 Monthly Notices of the Royal Astronomical Society
Rights© 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractWe show numerical simulations with monochromatic light in the visible for the LBTI Fizeau imager, including opto-dynamical aberrations due here to adaptive optics (AO) errors and to differential piston fluctuations, while other errors have been neglected. The achievable Strehl by the LBTI using two AO is close to the Strehl provided by a single standalone AO system, as long as other differential wavefront errors are mitigated. The LBTI Fizeau imager is primarily limited by the AO performance and by the differential piston/tip-tilt errors. Snapshots retain high-angular resolution and high-contrast imaging information by freezing the fringes against piston errors. Several merit functions have been critically evaluated in order to characterize point spread functions and the modulation transfer functions for high-contrast imaging applications. The LBTI Fizeau mode can provide an image quality suitable for standard science cases (i.e. a Strehl above 70 per cent) by performing both at a time: an AO correction better than approximate to lambda/18RMS for both short and long exposures, and a piston correction better than approximate to lambda/8 RMS for long exposures or simply below the coherence length for short exposures. Such results, which can be applied to any observing wavelength, suggest that AO and piston control at the LBTI would already improve the contrast at near-and mid-infrared wavelengths. Therefore, the LBTI Fizeau imager can be used for high-contrast imaging, providing a high-Strehl regime (by both AO systems), a cophasing mode (by a fringe tracker) and a burst mode (by a fast camera) to record fringed speckles in short exposures.
VersionFinal published version