Patent ID: 8866110

Claim:
A method comprising: releasing target material from an initial location toward a target region, the target material comprising a material that emits extreme ultraviolet (EUV) light when converted to plasma; interacting a pulse of light with the target material while the target material is between the initial location and the target region, the interaction producing a spatially extended target distribution having a larger extent in a direction that is different from a direction of propagation of the pulse of light than the target material; positioning an optic to establish a beam path that intersects the target region; coupling a gain medium to the beam path, the gain medium spontaneously emitting at least one photon onto the beam path; and interacting photons emitted from the gain medium with the spatially extended target distribution, when the spatially extended target distribution is in the target region, to produce an amplified light beam that converts at least some of the target material in the spatially extended target distribution to plasma that generates EUV light.