The Binary 2 surface is often used for achromatization. Consider a simple singlet lens in which the longer wavelength focuses at a larger Z distance from the lens than the short wavelength. A rotationally symmetric DOE such as Binary 2 surface can be used to minimize the longitudinal color.

Figure 13.13 of Optical System Design

Let's go through the process of designing the Binary 2 optics in the above figure. If you are not familiar with any of the steps in the exercise, please refer to the article Designing a Singlet in ZEMAX.

We will design a DOE using the Binary 2 surface with diffraction order m=1 to correct longitudinal color. The completed design can be downloaded from the last page of this article.

Set the system length units to mm (System > General > Units)
Set the system aperture as Entrance Pupil Diameter of 30 mm (System > General > Aperture)
Set the wavelength to F, d and C. (System > Wavelengths); select "F,d,C" from the drop-down menu in the Wavelength Data window.
Set one field with values X=0 and Y=0 (System > Fields)

Set surfaces in the LDE with following parameters.




The 3D layout shows the singlet.