General extended-object wavefront sensor: principles and applications

Wavefront sensing directly from extended objects is of significant importance for adaptive optics (AO), because most targets to be observed are extended ones. Up to now, widely used wavefront sensors are almost all dependent on point sources which are very difficult to be found in reality. In this paper, the approach of wavefront sensing directly from extended objects in AO is presented by using the general extended-object wavefront sensor (GEWFS). The configuration of the GEWFS is specially designed to enable each subaperture of the sensor to collect the same information of the object to be observed. In this way, the point spread function for every subaperture of the GEWFS can be extracted by eliminating the Fourier spectra of the extended object to be observed for further wavefront reconstruction. The GEWFS is then applied into aberrations correction in a transverse multimode laser diode and high-quality imaging of an extended object. The successful applications of the GEWFS show that the sensor is effective and feasible to be used in AO for wavefront sensing directly from extended objects.