• Title/Summary/Keyword: Wavefront Reconstruction

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Atmospheric Disturbance Simulation in Adaptive Optics: from Theory to Practice (적응광학에서의 대기 외란 모사: 이론에서 실제 적용까지)

  • Jun Ho Lee;Ji Hyun Pak;Ji Yong Joo;Seok Gi Han;Yongsuk Jung;Youngsoo Kim
    • Korean Journal of Optics and Photonics
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    • v.35 no.5
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    • pp.199-209
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    • 2024
  • Predicting the performance of adaptive optics systems is a crucial step in their design and analysis. First-order prediction methods, based primarily on several assumptions and scaling laws, are commonly used. These methods must account for various parameters and error sources, such as the intensity and profile of atmospheric turbulence, fitting errors based on the resolution of the wavefront sensor and deformable mirror, wavefront-sensor noise propagated through the wavefront-reconstruction algorithm, servo lag due to the finite bandwidth of the control loop, and anisoplanatism caused by the arrangement of natural and laser guide stars. However, since first-order performance-prediction methods based on certain assumptions can sometimes yield results that deviate from real-world performance, evaluation through computational simulations and closed-loop tests on a testbed is necessary. Additionally, an atmospheric simulator is required for closed-loop testing, which must adequately simulate the spatial and temporal characteristics of atmospheric disturbances. This paper aims to present an overview of the theory of atmospheric disturbance simulators, as well as their implementation in computational simulation and hardware.

Wave-Front Error Reconstruction Algorithm Using Moving Least-Squares Approximation (이동 최소제곱 근사법을 이용한 파면오차 계산 알고리즘)

  • Yeon, Jeoung-Heum;Kang, Gum-Sil;Youn, Heong-Sik
    • Korean Journal of Optics and Photonics
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    • v.17 no.4
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    • pp.359-365
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    • 2006
  • Wave-front error(WFE) is the main parameter that determines the optical performance of the opto-mechanical system. In the development of opto-mechanics, WFE due to the main loading conditions are set to the important specifications. The deformation of the optical surface can be exactly calculated thanks to the evolution of numerical methods such as the finite element method(FEM). To calculate WFE from the deformation results of FEM, another approximation of the optical surface deformation is required. It needs to construct additional grid or element mesh. To construct additional mesh is troublesomeand leads to transformation error. In this work, the moving least-squares approximation is used to reconstruct wave front error It has the advantage of accurate approximation with only nodal data. There is no need to construct additional mesh for approximation. The proposed method is applied to the examples of GOCI scan mirror in various loading conditions. The validity is demonstrated through examples.