Characterisation of adaptive optic pyramid wavefront sensors fabricated by deep X-ray lithography

Abstract

A novel type of wavefront sensor for adaptive optics, utilizing a pyramidal prism in the focus of a telescope, has recently been reported. The key part, the pyramid wavefront sensor, requires accurate control of the quality of the turned edges, the surfaces and the size of the pyramid tip. The classical figuring and polishing techniques used so far to fabricate the pyramid are time consuming and do not guarantee uniform repeatability of the optical characteristics required for the implementation of a large number of these devices for multi-conjugated adaptive optics. We propose a new manufacturing method for the pyramid sensors using the deep X-ray lithography process, allowing very precise control of the surfaces of the components produced. The fabrication method and characterisation of the first pyramids are presented.