An on-axis four mirror anastigmat telescope includes an entrance pupil configured to receive light from an image, and a mirror assembly. The mirror assembly has a first reflective surface having a central aperture formed therein, a second reflective surface, a third reflective surface having a central aperture formed therein, a fourth reflective surface, and an aperture stop. The mirror assembly is configured to receive light from the image on a common axis and to reflect the light successively by the four coaxial reflective surfaces through the aperture stop. The telescope further comprises a detector configured to receive light from the mirror assembly. The central aperture formed in the first reflective surface defines a field stop to limit the field of view.

A catadioptric lens includes at least two optical elements arranged along an optical axis. Both optical elements are configured as a mirror having a substrate and a highly reflective coating applied to an interface of the substrate. The highly reflective coating extends from the interface of the substrate along a surface normal. At least one of the highly reflective coatings has one or a plurality of layers. The optical total layer thickness of the one layer of the plurality of layers increases radially from the inner area outward.

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.

Optical system includes a front group, light-shielding member, and rear group that are arranged in this order in direction from object side toward image side. The light-shielding member is provided with opening elongated in first direction. The front group does not image the object at the opening in first section parallel to the first direction and forms intermediate image of the object at the opening in second section perpendicular to the first direction. The rear group has diffractive surface that splits light beam that passes through the opening into light beams at different wavelengths in the second section and focuses the light beams on different locations in the second section. Light beam that is emitted from the front group 11 and that enters the opening is non-parallel light in the first section.

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.

A device for converting electromagnetic radiation into electricity comprises an expander that includes a conical shape having an axis and a curved surface that is configured to reflect electromagnetic radiation away from the axis to expand a beam of the electromagnetic radiation; and one or more energy conversion components configured to receive a beam of electromagnetic radiation expanded by the expander, and to generate electricity from the expanded beam of electromagnetic radiation. With the expander's curved surface, a beam of electromagnetic radiation that is highly concentratedhas a large radiation fluxmay be converted into a beam that has a larger cross-sectional area. Moreover, one can configure, if desired, the curved surface to provide a substantially uniform distribution of radiation across the expanded cross-sectional area. With such an expanded beam the one or more energy conversion components can efficiently convert some of the electromagnetic radiation into electricity.

Optical system includes a front group, light-shielding member, and rear group that are arranged in this order in direction from object side toward image side. The light-shielding member is provided with opening elongated in first direction. The front group does not image the object at the opening in first section parallel to the first direction and forms intermediate image of the object at the opening in second section perpendicular to the first direction. The rear group has diffractive surface that splits light beam that passes through the opening into light beams at different wavelengths in the second section and focuses the light beams on different locations in the second section. Light beam that is emitted from the front group 11 and that enters the opening is non-parallel light in the first section.

An on-axis four mirror anastigmat telescope includes an entrance pupil configured to receive light from an image, and a mirror assembly. The mirror assembly has a first reflective surface having a central aperture formed therein, a second reflective surface, a third reflective surface having a central aperture formed therein, a fourth reflective surface, and an aperture stop. The mirror assembly is configured to receive light from the image on a common axis and to reflect the light successively by the four coaxial reflective surfaces through the aperture stop. The telescope further comprises a detector configured to receive light from the mirror assembly. The central aperture formed in the first reflective surface defines a field stop to limit the field of view.

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.

The present invention provides a projection optical system including a first concave reflecting surface, a first convex reflecting surface, a second concave reflecting surface, and a third concave reflecting surface, wherein the first concave reflecting surface, the first convex reflecting surface, the second concave reflecting surface, and the third concave reflecting surface are arranged such that light from an object plane forms an image on an image plane by being reflected by the first concave reflecting surface, the first convex reflecting surface, the second concave reflecting surface, the first convex reflecting surface, and the third concave reflecting surface in an order named.