Solid state laser medium and laser medium heat transfer method

A low-distortion solid state laser medium comprising:

• alternating layers of at least one laser gain element and at least one cooling element mated at an interface, wherein the gain element and cooling element are have disk-like aspect ratios and are layered to form a cylindrical gain rod, said interface having a center point at or near the optic axis of the laser medium,
• wherein the surface of at least one of the gain element and cooling element is physically modified at the interface such that the heat transfer coefficient at the interface decreases radially from the center point according to equation (1):
• h(r)=γ0l/└ΔTds0+γ0r2/(4κd)┘ (1)
• where h(r) is the heat transfer coefficient, γ0 is the heat input, 2 l is the thickness of the gain element, ΔTds0 is the temperature difference between the gain element and the cooling element at r=0, r is the radial distance from the optical axis at the center of the gain rod, and κd is the thermal conductivity of the cooling element.