An optical assembly, for receiving light waves, includes a receiving optical system for focusing at least one incoming light wave onto a surface of a detector for detecting the at least one light wave, at least one diffractive optical element with a planar extension being situated between the receiving optical system and the detector, and the at least one diffractive optical element including a surface with a surface structure with at least one optical function. Furthermore, a LIDAR device includes an optical assembly of this type.