| Wave-front sensing technology is the main components of adaptive optics, andplay a role in the detection of errors caused by atmospheric turbulence inground-based telescopes. Currently several technologies are widely used, includingShack-Hartmann wave-front sensor, shearing interferometer, and curvature sensors.Pyramid wave-front sensor is a new wave-front sensing technology, with highprecision, energy efficiency, simple calculation, and the ability to adjust the dynamicrange and accuracy in a wide range.Pyramid wave-front sensing system is based on Foucault knife-edge test.Pyramid serves as both phase filter and spectral filtering. Through modulation,namely oscillating pyramid, one can change its dynamic range and accuracy. Nowthis technology has been more and more studied, and has been applied in someObservatory.In order to verify the effectiveness and pyramid technology further study, thispaper completed the following tasks: to study the different operating modes andvarious improvements structure of pyramid wave-front sensor, the establishment of amathematical model, and comparison with Hartman wave-front sensor; thesimulation of atmospheric based on random atmospheric turbulence power spectrum,as the system’s input; numerical simulation using MATLAB, testing its performanceunder different input, including a single mode Zernike aberrations, and atmosphericturbulence random phase screen; modulation and non-modulation modes and their reconstruction were validated, and the influence of modulation radius were tested.Simulation results show that pyramid sensor has high accuracy, as that RMS can becontrolled under0.02, and, with the change of modulation parameters, dynamicrange can improve in the cost of accuracy, which facilitates the application ofdifferent environments. Experiment is designed using a spatial light modulator as anexperimental optical path splitting device. The processing parameters of a glasspyramid are determined. |
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