Disk laser

A laser apparatus comprising:

• a substrate configured to increase an intensity of light at a desired wavelength, the substrate comprising:
• a plurality of sections
• first suppression material at a number of locations within each section of the plurality of sections, the first suppression material comprises different sizes and shapes at each location of the number of locations;
• an outer edge outside of which is second suppression material;
• the second suppression material also located between each section of the plurality of sections;
• each section of the plurality of sections doped with a first dopant to amplify light at the desired wavelength;
• the first suppression material and the second suppression material are doped with a second dopant to attenuate transmission of light;
• and
• a cooling system for the substrate configured to allow gas to be transmitted through the cooling system and receive heat generated in the substrate from a back side of the substrate, wherein the gas is liquefied gas;
• wherein a concentration of the first dopant changes over a distance so that the concentration is less at the edge of each section of the plurality of sections than in a middle portion of each section of the plurality of sections.