A material having a surface and a dopant in the material distributed whereby the material has a spatially variant optical flux density profile. In accordance with the invention, tailored non-uniform gain profiles within a Yb:YAG laser component (rod, slab, disc, etc.) are achieved by a spatial material modification in the spatially masked pre-forms. High temperature-assisted reduction leads to the coordinate-dependent gain profiles, which are controlled by the topology of the deposited solid masks. The gain profiles are obtained by reducing the charge state of the laser-active trivalent Yb3+ ions into inactive divalent Yb2+ ions. This valence conversion process is driven by mass transport of ions and oxygen vacancies. These processes, in turn, affect the dopant distribution throughout the surface and bulk laser crystal. By reducing proportionally more Yb3+ ions at the unmasked areas of component, than in the masked areas, the coordinate-dependent or spatially-controlled gain profiles are achieved. Preferred masking materials are high temperature ceramic glazes and glasses. The masking includes the fabrication of frit, mixing this frit with de-ionized water to form slurry, deposition of the slurry on the surface of laser component or pre-form, and a heat treatment (firing) of the deposited layer. The invention can be used for the fabrication of laser rods, slabs, etc. with various concentrations and spatial localizations of dopants.