A method of correcting apodization in an optical system includes
determining effects of apodization on an intensity distribution of a beam
of radiation in a predetermined plane of the optical system; determining
a more desirable intensity distribution of the beam of radiation in the
predetermined plane such that apodization is corrected for; and absorbing
portions of the beam of radiation in the predetermined plane as a
function of location such that downstream from the predetermined plane
the beam of radiation shows the more desirable intensity distribution. An
optical component includes one or more absorbing layers designed to
perform the absorption as a function of the location. The optical
component may located in the pupil plane of the optical system.