Modulation-nonmodulation pyramid wavefront sensor with direct gradient reconstruction algorithm on the closed-loop adaptive optics system

A modulation-nonmodulation pyramid wavefront sensor with direct gradient reconstruction algorithm using on the adaptive optics is reported in this paper. This means that the interaction matrix of the system is obtained by using a modulated pyramid and the closed-loop control process is performed with a nonmodulated pyramid. The theoretical basis and simulation analysis of the direct gradient reconstruction algorithm are described in detail, and laboratory results show that the pyramid wavefront sensor based on this algorithm can work as expected in a closed-loop adaptive optics system.