Pyramidal wavefront sensor using diffractive lenses

A new technique for high resolution wavefront sensing has been introduced. It is based on the Optical Differentiation wavefront sensor, however its application has required the development of a diffractive element that provides four or five copies of the original wavefront. It some aspect the result is similar to that provide by the Pyramid sensor although from a theoretical point of view is more close to the Modified Hartmann sensor. Here we introduce the theoretical background and principles along with an example of phase derivative estimate based on a computer simulation. The technique looks very promising since it is simple, with high resolution, without moving parts and allows us an easy post processing to recover Zernike coefficients. Nevertheless, a lot of work has to be completed to a proper evaluation of its actual capabilities, noise, resolution, etc.