A multi channel beamsplitter system operating over a wide spectral band has high optical performance despite the fact that the incoming and/or exiting light is not collimated and its material is dispersive. This is achieved using wavefront compensators that are matched to the curvature of the wavefronts of the incoming and/or exiting light.

An optical system to divide a light flux from an object plane includes a first curved-surface mirror, and second, third, and fourth reflecting portions. The second reflecting portion divides and reflects light flux from the first curved-surface mirror to respective different positions on the first curved-surface mirror as first light fluxes. The third reflecting portion reflects, as third light fluxes, the first light fluxes. The fourth reflecting portion reflects the third light fluxes from the third reflecting portion. A number of reflective surfaces of each of the third and fourth reflecting portions on which the first and third light fluxes are incident is the same as a division number in the dividing of the light flux into the second light fluxes. The first and third light fluxes are reflected by the respective third and fourth reflecting portions to be image-formed so that divided images of the object plane are formed.

A device for optically imaging at least a part of an object, the device having an optical axis and including a two-dimensional first array of first microlenses, having a first side intended to face the object, and a second side, opposite the first side, a two-dimensional second array of second microlenses, each first microlens being aligned with a second microlens on an axis parallel to the optical axis, wherein each first microlens comprises a first catoptric system, and preferably a first catadioptric system.

An imaging optical system has a plurality of mirrors which image an object field in an object plane in an image field in an image plane. The imaging optical system has a pupil obscuration. The last mirror in the beam path of the imaging light between the object field and the image field has a through-opening for the passage of the imaging light. A penultimate mirror of the imaging optical system in the beam path of the imaging light between the object field and the image field has no through-opening for the passage of the imaging light. The result is an imaging optical system that provides a combination of small imaging errors, manageable production and a good throughput for the imaging light.

A device for optically imaging at least a part of an object, the device having an optical axis and including a two-dimensional first array of first microlenses, having a first side intended to face the object, and a second side, opposite the first side, a two-dimensional second array of second microlenses, each first microlens being aligned with a second microlens on an axis parallel to the optical axis, wherein each first microlens comprises a first catoptric system, and preferably a first catadioptric system.

Disclosed are methods and apparatus for reflecting, towards a sensor, an Infrared to vacuum ultra-violet (VUV) light that is reflected from a target substrate. The system includes a first mirror arranged to receive and reflect the Infrared to VUV light that is reflected from the target substrate and a second mirror arranged to receive and reflect Infrared to VUV light that is reflected by the first mirror. The first and second mirrors are arranged and shaped so as to reflect Infrared to VUV light from the target substrate towards an optical axis of the apparatus. In another embodiment, the apparatus can also include a third mirror arranged to receive and reflect the Infrared to VUV light that is reflected by the second mirror and a fourth mirror arranged to receive and reflect such illuminating light that is reflected by the third mirror towards the sensor. In one more embodiment, a reflecting or refracting optics is used to relay the image by above optics to the sensor; various magnification is achieved by adjusting the distance between the intermediate image and the relay optics.

An imaging optical unit for projection lithography has a plurality of mirrors for guiding imaging light from an object field in an object plane into an image field in an image plane along an imaging light beam path. At least two of the mirrors are embodied as GI mirrors. Exactly one stop serves to predefine at least one section of an outer marginal contour of a pupil of the imaging optical unit. The stop is arranged spatially in front of a penultimate mirror in the imaging light beam path. This results in an imaging optical unit that is well defined with regard to its pupil and is optimized for projection lithography.

An imaging optical unit for EUV projection lithography serves to image an object field into an image field. Mirrors guide imaging light from the object field to the image field. An aperture stop is tilted by at least 1 in relation to a normal plane which is perpendicular to an optical axis. The aperture stop has a circular stop contour. In mutually perpendicular planes, a deviation of a numerical aperture NA.sub.x measured in one plane from a numerical aperture NA.sub.y measured in the other plane is less than 0.003, averaged over the field points of the image field. What emerges is an imaging optical unit, in which homogenization of an image-side numerical aperture is ensured so that an unchanging high structure resolution in the image plane is made possible, independently of an orientation of a plane of incidence of the imaging light in the image field.

A method for designing an imaging objective lens system with an anamorphic magnification. The method includes the following steps: designing a coaxial overall spherical imaging objective lens system A with an M magnification; only using the curvatures of reflectors in the system A as optimization variables to optimize the system A into a system B with an N magnification; transforming the reflectors in the system A to have an anamorphic aspherical surface profile, wherein the longitudinal curvature of each anamorphic aspherical surface remains unchanged, and the transverse curvature is the curvature of the corresponding reflector in the system B; and obtaining an anamorphic magnification imaging system C with an M longitudinal magnification and an N transverse magnification. The imaging objective lens system designed with the method can realize different magnification in different directions.

An optical assembly (1) includes an optical element (2), a mount (3) configured to hold the optical element (2), and a plurality of fastening elements (12) with fastening areas (14) configured to fasten the optical element (2) to the mount (3). The fastening elements (12) bridge an interstice (11) between the optical element (2) and the mount (3), and a purge device (15) produces at least one purge gas flow (16) in the region of the optical element (2) such that the purge gas flow flows around the fastening areas (14) of the fastening elements (12).