<title>Diamond-turned diffractive optical elements for the infrared: suggestion for specification standardization and manufacturing remarks</title>

Diffractive optical elements (DOEs) have found their acceptance in lens design as an additional tool to refractive and reflective elements. They are especially powerful for applications in the infrared spectrum, because many of the materials, suitable for transmission in this region, lend themselves exceptionally well to the correction of chromatic aberration. The phase profile of the grating superimposed onto the base surface of an IR lens is relatively coarse. This makes it economically advantageous to apply the single point diamond-turning process to the direct generation of such phase profiles. Different ways have been used to describe the profile of a DOE, which have in some cases led to costly misunderstandings. To provide some clarification and suggest a form of standardization for the specifications call-out in manufacturing documents is the primary purpose of this paper. Additional comments are being presented as guidelines and for better understanding of the advantages and limitations for applications of diffractive optical elements in general, and of diamond-turned elements in particular.