Planarization of defects in laser mirror and other optical component manufacture is disclosed. The planarization is performed by first depositing a relatively thick planarization layer, then carrying out a sequential deposition and etch process. The technique takes advantage of the non-uniform material removal rate as a function of etchant incident angle, and effectively buries the inclusion in a thick film with a near planar top surface. The process enables faster, more reliable manufacture of a non-defective high fluence multilayer mirror particularly suitable for high energy laser applications.