High-definition quadriwave lateral shearing interferometry.

We present an evolution of quadriwave lateral shearing interferometry that improves the definition of quantitative phase images. It is now possible to produce images with as many pixels as the camera that records the interferogram. This is done by moving a diffraction grating in front of the camera and linearly combining at least nine acquisitions. In this paper, we present the principle of this technique and illustrate it by several examples acquired on a microscope with both calibrated and biological samples. We demonstrate the possibility of producing quantitative phase images with 5.5 million pixels, which are to our knowledge the largest images ever produced by a wavefront sensor.