Simultaneous lateral shearing-interferometry

Last year, we presented a method capable of providing a simultaneous measurement of the gradients of wavefronts along orthogonal directions using lateral shearing interferometry. The wavefront itself is then reconstructed via numerical integration. Both orthogonal components are measured on the same detector grid to minimize global distortions of the imaging optical elements and to avoid the difficult adjustment of the two gradient fields with respect to the coordinate system of the detector. The shear is realized by two ronchi-phase-gratings connected in series. Until now, the necessary discrimination of the two gradient fields has been done by a revolvable polarizer. In this contribution we examine two possibilities to achieve the separation without moving parts in the setup and at the same time: on the one hand a mathematical separation in the Fourier domain by using tilted wavefronts and on the other hand an indication via polarisation together with a pixelated polarisation array in front of the camera.