An off-axis three-mirror optical system with freeform surfaces comprised an aperture, a primary mirror, a secondary mirror, a tertiary mirror, and a detector. The aperture is located on an incident light path. The primary mirror is located on an aperture side. The secondary mirror is located on a primary mirror reflected light path.

The tertiary mirror is located on a secondary mirror reflected light path. The detector located on a tertiary mirror reflected light path. The primary mirror and the tertiary mirror have a same fifth-order polynomial freeform surface expression. The primary mirror reflected light path, the secondary mirror reflected light path and the tertiary mirror reflected light path overlap with each other.

According to various embodiments, a direct magnetic gradiometer having intrinsic subtraction of rotation signals from two oppositely polarized atomic ensembles within a single multi-pass cell is disclosed. The gradiometer includes three convex spherical mirrors aligned in a V-shape geometry. The three convex spherical mirrors include a front mirror and two back mirrors. The gradiometer further includes a probe laser beam. The laser beam is configured to be initially focused at a near-zero angle into a hole at a center of the front mirror such that the laser beam expands at the back mirrors and nearly overlaps with itself while undergoing multiple reflections between the front and back mirrors. The laser beam is further configured to be refocused to the front mirror at different spots in a number equal to half of total beam passes before exiting.

A freeform surface off-axial three-mirror imaging system comprising a primary mirror, a secondary mirror, a tertiary mirror, and an image sensor. Each reflective surface of the primary mirror, the secondary mirror, and the tertiary mirror is an xy polynomial freeform surface. A field angle of the freeform surface off-axial three-mirror imaging system is larger than or equal to 60°×1°. An F-number of the freeform surface off-axial three-mirror imaging system is less than or equal to 2.5.

A catoptric system having a reference axis and including a reflective pattern-source (carrying a substantially one-dimensional pattern) and a combination of only three optical components disposed sequentially to transfer EUV radiation incident the first optical component onto the pattern-source. The combination is disposed in a fixed spatial and optical relationship with respect to the pattern-source, and represents an illumination unit (IU) of a 1D EUV exposure tool that additionally includes a projection optic sub-system configured to form an optical image of the pattern-source on an image plane with the use of only two beams of radiation. These only two beams of radiation originate at the pattern-source from the EUV radiation transferred onto the pattern-source.

Techniques are disclosed for mounting optical elements in optical systems. A system may include a mirror assembly. The mirror assembly may include a mounting stem and a mirror. The system may further include a mounting ring. The system may further include a metering structure. The metering structure may include a receiving interface having an inner surface defining an aperture. The metering structure may be configured to receive the mounting stem within the aperture and receive the mounting ring within a gap between the mounting stem and the inner surface. The system may further include a bonding layer disposed between the mounting stem and the mounting ring. Additional apparatus and related methods are provided.

A point-by-point design method for off-axis aspheric optical system, in which feature light rays from different field angles and aperture coordinates are considered. Some of the feature data points are calculated first and surface fitted into an initial aspheric surface. Then, intermediate point calculations, feature data point calculations, and aspheric surface fitting were repeated continuously to calculate remaining feature data points and the desired aspheric surface are repeated continuously to calculate remaining feature data points and a desired aspheric surface. A least-squares method with a local search algorithm is used for aspheric surface fitting and deviations in both the coordinates and normals are used to reduce error.

A catoptric system having a reference axis and including a reflective pattern-source (carrying a substantially one-dimensional pattern) and a combination of only three optical components disposed sequentially to transfer EUV radiation incident the first optical component onto the pattern-source. The combination is disposed in a fixed spatial and optical relationship with respect to the pattern-source, and represents an illumination unit (IU) of a 1D EUV exposure tool that additionally includes a projection optic sub-system configured to form an optical image of the pattern-source on an image plane with the use of only two beams of radiation. These only two beams of radiation originate at the pattern-source from the EUV radiation transferred onto the pattern-source.

A spectrophotometric device is disclosed having a plurality of spectral measurement bands including a single telescope and a single spectrophotometer. The plurality of spectral bands is obtained by placing pupillary separating prisms at an entrance pupil of the telescope, and by using spectral band selection filters. Such a device has a lower weight, smaller dimensions, and a lower price. In particular, it may be integrated into a satellite, in particular for a mission to characterize flows of carbon compounds that are produced on the Earth's surface.

A method for designing an off-axis three-mirror imaging system with freeform surfaces is provided. A primary mirror initial structure, a secondary mirror initial structure, and a tertiary mirror initial structure are established. A number of first feature rays are selected, while the primary mirror initial structure and the secondary mirror initial structure unchanged. The first feature rays are forward ray tracked from an object space to an image detector. A number of first feature data points are calculated to obtain a tertiary mirror. A number of fields and a number of second feature rays are selected, while the secondary mirror initial structure and the tertiary mirror unchanged. The second feature rays are reverse ray tracked from the image detector to the object space. A number of second feature data points are calculated to obtain the primary mirror.

A spectrophotometric device is disclosed having a plurality of spectral measurement bands including a single telescope and a single spectrophotometer. The plurality of spectral bands is obtained by placing pupillary separating prisms at an entrance pupil of the telescope, and by using spectral band selection filters. Such a device has a lower weight, smaller dimensions, and a lower price. In particular, it may be integrated into a satellite, in particular for a mission to characterize flows of carbon compounds that are produced on the Earth's surface.