Patent ID: 7714986

Claim:
A radiation beam conditioning system, configured to condition a pulsed beam of radiation for use in a lithographic apparatus, the radiation beam conditioning system comprising: a radiation beam divider configured to divide the pulsed beam of radiation along at least first, second and third optical paths; a radiation beam combiner configured to re-combine the pulses of radiation from the at least first, second, and third optical paths to form a single output pulsed beam of radiation; and a radiation pulse trimmer configured to the pulse of radiation traveling along the first optical path, wherein the radiation pulse trimmer is configured to trim the pulse of radiation within the first optical path, such that a total amount of energy of the single output pulsed beam of radiation is substantially a predetermined level, and wherein optical path lengths of the first, second and third optical paths, between the radiation beam divider and the radiation beam combiner, are different.