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- Title
Adaptive optics correction based on stochastic parallel gradient descent technique under various atmospheric scintillation conditions: numerical simulation.
- Authors
Ma, H.; Fan, C.; Zhang, P.; Zhang, J.; Qiao, C.; Wang, H.
- Abstract
An adaptive optics system utilizing a Shack-Hartmann wavefront sensor and a deformable mirror can successfully correct a distorted wavefront by the conjugation principle. However, if a wave propagates over such a path that scintillation is not negligible, the appearance of branch points makes least-squares reconstruction fail to estimate the wavefront effectively. An adaptive optics technique based on the stochastic parallel gradient descent (SPGD) control algorithm is an alternative approach which does not need wavefront information but optimizes the performance metric directly. Performance was evaluated by simulating a SPGD control system and conventional adaptive correction with least-squares reconstruction in the context of a laser beam projection system. We also examined the relative performance of coping with branch points by the SPGD technique through an example. All studies were carried out under the conditions of assuming the systems have noise-free measurements and infinite time control bandwidth. Results indicate that the SPGD adaptive system always performs better than the system based on the least-squares wavefront reconstruction technique in the presence of relatively serious intensity scintillations. The reason is that the SPGD adaptive system has the ability of compensating a discontinuous phase, although the phase is not detected and reconstructed.
- Subjects
ADAPTIVE optics; SCINTILLATION spectrometry; HOLOGRAPHY; BANDWIDTHS; SOUND measurement; PERFORMANCE evaluation; KEY performance indicators (Management); COMPUTER simulation
- Publication
Applied Physics B: Lasers & Optics, 2012, Vol 106, Issue 4, p939
- ISSN
0946-2171
- Publication type
Article
- DOI
10.1007/s00340-012-4928-6