Patent ID: 7561611

Claim:
An extended lifetime element for use in high power excimer lasers, said element comprising: a substrate; an aluminum film deposited on the surface of the substrate, wherein the aluminum film is not oxidized; and one or a plurality of protective dielectric material layers applied to the surface of said aluminum film, each of said one or plurality of layers having a thickness in the range of 20- 150 nm; wherein the thickness of the one layer or the first of a plurality of dielectric layers comprises: a first sub-layer of thickness 4-8 nm densified by bombardment of energetic inert gas, not including oxygen, ions on top of the aluminum film and a second sub-layer of thickness 12-146 nm densified by bombardment of energetic inert-gas-and-oxygen ions on top of the first sub-layer, and wherein the sum of the total thickness of the first densified sub-layer and the second densified sub-layer is in the range of 20-150 nm.