Design and development of Shack–Hartmann wavefront sensor-based testing of high-resolution optical system for earth observation

Abstract

The deformation of the optical surfaces of a large aperture high-resolution space-borne optical system induced by earth’s gravity on the ground, which is not present during in-orbit operations, necessitates the evaluation of its performance in terms of wavefront error at various stages of development of the earth observation system. A direct method of evaluation for an optical system at an integrated electro-optical module based on a Shack–Hartmann wavefront sensor (SH WFS) is proposed. Design and analysis of the wavefront sensor that are tailored to meet the requirements of the high-resolution optical system are described. We show that the procedure followed for the development of the SH WFS not only addresses the parameters of the wavefront sensor that are critical to its performance, but also aides in the wavefront sensor alignment and calibration. The performance of the developed SH WFS is demonstrated by testing a simulated telescope which is <italic<in situ</italic< verified in a test configuration using a standard Fizeau interferometer; a close match of the coefficients of Zernike modes between them is established.