The Light Beam Wavefront Correction With The Beacon

The detection and correction of the aberration caused by the turbulent atmosphere are very important for the wave propagations and astronomic imaging. Some error sources of the Hartmann-Shack wavefront sensors are discussed in the paper, the errors of the detected centroid is the main theme here.Some advises to reduce the errors of wavefront detection are given after the analyses of the errors model. Different wavefront reconstructing models of H-S wavefront sensor are presented, the efficiency of each iteration and the error propagation properties of each reconstruction models are compared here.With the control program baseing on the optimal selection and a deformable mirror with 52 actors, the static aberration of the optical system corrected well. The wavefront of star light is analized.We generated artifical Ruily Laser Guide Star, and measured the wave front of the beacon. All the result show that the tilt is the main part of the aberration caused by the turbulent atmosphere, and the artifical beacon can not provide the tilt for the adaptive optical system. Two active methods of generating a useful beacon are discussed with a numeric simulation of the turbulent atmosphere. Propagation of electromagnetic energy through the atmosphere is a difficult task because of temperature fluctuations and index-of-refraction inhomogeneities which degrade the beam?coherence. Describing the effect of the turbulent atmosphere with the index-of-refraction structure function,we simulate the beam propagating in the horizontal path with a two-dimensional gaussian phase screens.An efficient two-dimensional FFT subroutine are used in approximating the diffraction integrals. The far-field sparkles of illuminating with multiple lasers are reckoned up with the atmosphere propagating model formed in chapter 2. There are some analyses about the characteristics of the sparkle under focussing and defocussing illumination.