HOE is a kind of diffraction element. So you can either use RCWA or FDTD to get the result, then import to Zemax. Please refer this exmaple:
https://optics.ansys.com/hc/en-us/articles/18427154870803-Lumerical-Sub-wavelength-Model-Usage-in-Zemax-OpticStudio
and
https://optics.ansys.com/hc/en-us/articles/18254409091987-Large-Scale-Metalens-Ray-Propagation
You are navigating away from the AIS Discovery experience