Effect of Aberrations on the Self-Imaging Phenomenon

Diffraction gratings are used in measurement devices for scientific and industrial applications. As it is well known, self-images appear in the near field when diffraction gratings are illuminated with a coherent beam, such as a plane wave. This effect has been analyzed in depth and its behavior is well known under ideal grating and illumination conditions. Usually, the illumination beam is not perfectly collimated but it presents a certain degree of aberration. In this work we analyze the behavior of the self-images of an ideal amplitude grating when it is illuminated by an aberrated beam. As it is expected the contrast of the self-images decrease when the order of them increases and also when the aberration degree increases. In some cases, contrast inversion is also produced for high degree aberrations.