title: Wavefront sensing using diffractive elements.
abstract: In this Letter, we introduce a wavefront slope sensor based on a diffractive element. The diffractive element wavefront sensor (DEWS) produces four double overlapping copies of the incoming wavefront acting like a combination of shearing and pyramidal sensors. The DEWS allows a simple and fast slope estimate. The wavefront sampling can be as high as the number of pixel assigned to cover a wavefront copy, and it can be modified with only binning the CCD pixels. The theory for designing the sensor, its application to extract local slope information, and a simple noise analysis are presented. An application example for atmosphere aberrated wavefronts is demonstrated.
authors.affiliation: Departamento de Física Aplicada, Universidad de Cantabria, Santander, Spain.
authors.forename: Manuel P
authors.initials: MP
authors.lastname: Cagigal
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Valle