Lens for microscopic inspection

An optical system comprising three lens sections, a catadioptric objective lens section, a reimaging lens section and a zoom lens section, which are all aligned along the optical path of the optical system. The reimaging lens section re-images the system pupil such that the re-imaged pupil is accessible separately from any of the lens sections. The reimaging lens section includes an intermediate focus lens group, which is used to create an intermediate focus, a recollimating lens group, which is used to recollimate the light traveling from the intermediate focus lens group, refocusing group to generate the re-image of the pupil. The optical system may also include a beamsplitter, which creates a separated illumination pupil and collection pupil. The illumination pupil and the collection pupil may then be manipulated with an illumination aperture and a collection aperture, respectively, so that the optical system may operate in various test modes such as brightfield, ring darkfield, full-sky illumination, and laser darkfield with Fourier filtering capability. Another aspect of the invention pertains to a method for using the broad spectral region catadioptric optical system. The method includes the operations of directing radiation from a radiation source so that the radiation passes through the illumination pupil and the collection pupil of the optical system. The method also includes operations for configuring the illumination pupil and the collection pupil so that the optical system may operate in brightfield, ring darkfield, full-sky or laser darkfield illumination mode, with Fourier filtering capability.