Wavefront control for complicated pupil space telescopes

摘要

There are several kinds of complicated pupil telescopes including sparse-aperture telescopes and segmented-aperture telescpoes. Misalignment or misfigure of these segments or subapertures results in wavefront errors which degrade the imaging quality. Wavefront control for complicated pupil space telescopes is necessary in the fabrication.Three kinds of techniques of wavefront control are introduced. These include phase diversity, in-focus PSF optimizer and coarse phasing with white light interferometry. The principles of three kinds of techniques are illustrated and compared.The performances as wavefront sensors are also introduced. Phase diversity is a combined collection and post-processing techique to infer unknow phase aberrations from image date. In-focus PSF optimizer is a parameter estimation process in which a computer-generated model PSF matches an observed PSF. Coarse phasing with white light interferometry uses the features of the white light PSF formed by complicated pupil space telescopes to detect and correct the piston between segments or sub-apertures. It is obvious that different methods of wavefront control have different characteristics. In order to solve the optical alignment for complicated pupil telescopes, different methods of wavefront controls are selected to complete the correction of errors based on the different situation.