Comparison of LGS wavefront-sensing with pyramid, yaw, and quad-cell types wavefront sensors
Résumé
LGS wavefront sensing is a topic of importance for future ELTs. However, the elongation effect makes this task particularly difficult on a large apertures, and require large format detectors. An alternative solution is to use quad-cell types wavefront sensors : either shack-hartmann, or pyramid (using only 4 pixels per phase measurement), or yaw (an optical differentiation wavefront sensor proposed recently, also using 4 pixels, like the pyramid). We compare the performance of these devices and we develop a common model of operation, so that their behavior can be directly compared and their differences easily enlightened.