Diffractive gratings with a varying period’s shape

Abstract

The aim of this short review is to recall various designs of diffraction gratings when the condition of the period’s identity is relaxed and to mention some of this resulting applications. Among others, the apodization function can be implemented as a variable diffraction efficiency due to a gradual change of the period’s shape. Another possible application is passive achromatization of diffraction efficiency of blazed gratings by randomizing their blaze angle.