Enhanced beam quality from a laser rod using interstitial dopants

A method for reducing the near surface absorption of incident photons intended to induce lasing in a laser rod using a layer of inactive laser ions, the laser rod having longitudinal axis and a radial periphery about the longitudinal axis, the method comprising:

• providing an as-grown laser rod having dopant ions of a first valence therein;
• placing pre-selected chemical constituents into intimate contact with the surface of the laser rod;
• and
• diffusing the chemical constituents into the laser rod as interstitial ions that reduce the valence state of the active laser dopant ions to a second valence, thereby decreasing the concentration of the active laser dopant ions of a first valence at the near-surface periphery region and thereby forming a radial-dependent concentration profile of the first valence state dopant ions that is minimized at the radial periphery as compared to the concentration of the first valence state dopant ions along the longitudinal axis, wherein a radial-dependent gain profile within the rod is formed.