23 December 2004 Preliminary numerical simulation investigation of the cone effect in an adaptive optics system using a laser guide star
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Proceedings Volume 5639, Adaptive Optics and Applications III; (2004); doi: 10.1117/12.573432
Event: Photonics Asia, 2004, Beijing, China
Abstract
So-called cone effect or focus anisoplanatism is produced by the limited distance of a laser guide star (LGS) which is created within the Earth atmosphere and consequently located at a finite distance from the observer. We believe this is the first time to investigate the cone effect of the LGS by means of a pure numerical simulation. In this paper, the cone effect of the LGS for different vertical profiles of the refractive index structure constant C2n is numerically investigated by using a revised computer program of atmospheric propagation of optical wave and an adaptive optics (AO) system including dynamic control process. It is surprisingly found that the effect of altitudes of the LGS on the AO phase compensation effectiveness by using the commonly-available vertical profiles of C2n and the lateral wind speed in the atmosphere is relatively weak, and the cone effect for some C2n profiles is even negligible. It is found that the cone effect seems not have obvious relationship with the turbulence strength, however, it depends on the vertical distribution profile of C2n apparently. On the other hand, the cone effect depends on the vertical distribution of the lateral wind speed as well. The cone effect becomes more obvious as the zenith angle increases. In comparison to a near infrared wavelength, the cone effect becomes larger in the case of the visible wavelength. In all cases concerned in this paper, an AO system by using a sodium guide star has almost same phase compensation effectiveness as that by using the astronomical target itself as a beacon.
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Hai-Xing Yan, Shu-Shan Li, She Chen, "Preliminary numerical simulation investigation of the cone effect in an adaptive optics system using a laser guide star", Proc. SPIE 5639, Adaptive Optics and Applications III, (23 December 2004); doi: 10.1117/12.573432; https://doi.org/10.1117/12.573432
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KEYWORDS
Adaptive optics

Process control

Numerical simulations

Atmospheric modeling

Atmospheric propagation

Control systems

Wavefronts

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