Wavefront sensing by numerical evaluation of diffracted wavefields

摘要

A novel wavefront sensor principle based on diffraction theory and Fourier analysis with a modified angular spectrum propagator has been developed. We observe the propagation of a wavefront behind a two-dimensional cross grating and derive a universal method to extract the phase gradient directly from a captured intensity image. To this end the intensity distribution is analyzed in the spectral domain, and the processing is simplified by an appropriate decomposition of the propagator kernel. This method works for arbitrary distances behind the grating. Our new formulation is verified through simulations. The wavefront generated by a freeform surface is measured by the new method and compared with measurements from a commercial Shack-Hartmann wavefront sensor. (C) 2016 Optical Society of America