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M. C. Britton, K. Taylor (California Institute of Technology)
This paper describes an adaptive optics concept that uses a single sodium laser beacon driving a single deformable mirror to achieve partial compensation of atmospheric turbulence over a relatively wide field of view. The angular size of the corrected field of view increases with aperture diameter, while the degree of partial compensation decreases with aperture diameter. For a 30 meter aperture, the corrected field of view is 70 arcseconds, while the wavefront variance is reduced by 90 percent under typical astronomical turbulence conditions. These values are independent of the observing wavelength. Within this field of view, the partially compensated point spread function displays a core-halo structure, where the width of the core is inversely proportional to the focal anisoplanatism term d0. Outside of this field of view the system performance degrades with increasing field angle, so that beyond some characteristic angle the residual wavefront variance exceeds that of the uncompensated wavefront. For a 30 meter aperture the field of view over which the system performance offers an improvement over seeing limited observations is of order 4 arcminutes for typical astronomical turbulence conditions. The partially compensated point spread functions delivered by this system are well suited for improving spectroscopic slit coupling efficiencies over larger fields, while the core-halo structure within the central field is useful for narrow field imaging and spectroscopic applications. The fact that this type of adaptive optics system effects only a partial compensation considerably loosens the requirements on other error terms, so that such a system can deliver performance improvements at wavelengths as low as 300 nm under favorable turbulence conditions.
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The author(s) of this abstract have provided an email address for comments about the abstract: mbritton@astro.caltech.edu
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.