Dc. Johnston et Bm. Welsh, ANALYSIS OF MULTICONJUGATE ADAPTIVE OPTICS, Journal of the Optical Society of America. A, Optics, image science,and vision., 11(1), 1994, pp. 394-408
We investigate a method for widening the compensated field of view of
an adaptive-optical telescope with multiple deformable mirrors and an
array of artificial guide stars. An ensemble of wave-front sensor meas
urements, made with the individual guide stars in the array, is used t
o estimate the contribution of a region of the atmosphere to the cumul
ative phase distortion. Our analysis includes the effects of measureme
nt noise, wave-front-sensor sampling, and reconstruction of the wave f
ront from slope measurements. We performed numerical computations for
an atmosphere consisting of two turbulent layers: one at 1% of the gui
de-star altitude with 90% of the total turbulence strength and one at
10% of the guide-star altitude with the remaining 10% of the total tur
bulence strength. If we assume that r(0) = 0.15 m and that a photon-li
mited wave-front sensor detecting 50 photons/r(0)-sized subaperture is
used, the results indicate that a 0.9-m-square telescope with a diago
nal field of view of similar to 92 mu rad approximate to 19 arcsec can
use two deformable mirrors, four laser guide stars, and a natural til
t reference star to achieve an rms residual phase error that is <lambd
a/7 over its entire field of view.