The present invention relates to a method, and a corresponding device, for testing a radius of curvature and/or for detecting inhomogeneities of a curved X-ray grating for a grating-based X-ray imaging device. The method comprises generating a beam of light diverging from a source point, propagating along a main optical axis and having a line-shaped beam profile. The method comprises reflecting the beam off a concave reflective surface of the grating. A principal axis of the concave reflective surface coincides with the main optical axis and the source point is at a predetermined distance from a point where the main optical axis intersects the concave reflective surface. The method comprises determining whether a projection of the reflected beam in a plane at or near the source point is present outside a central region around the source point, in which an absence of this projection outside the central region indicates that a radius of curvature of the concave reflective surface corresponds to the predetermined distance and/or that the reflective surface is substantially homogeneously curved along a curve formed by the beam impinging on the concave reflective surface.

Embodiments of the present disclosure relate to measurement systems and methods for diffracting light. The measurement system includes a stage, an optical arm, and one or more detector arms. The method of diffracting light includes a method of diffracting light is provided, including projecting light beams having wavelength .sub.laser to a first zone of a first substrate at the fixed beam angle .sub.0 and the maximum orientation angle .sub.max, obtaining a displacement angle , determining a target maximum beam angle .sub.t-max, wherein .sub.t-max=.sub.0=, and determining a test grating pitch P.sub.t-grating by a modified grating pitch equation P.sub.t-grating=.sub.laser/(sin .sub.0). The measurement system and method allow for measurement of nonuniform properties of regions of an optical device, such as grating pitches and grating orientations.

Systems and methods for testing and characterization of optical surfaces which works equally well on concave, flat, convex, and non-conic optical surfaces, and which does not require that a master surface be first produced. The method is automatic and requires little human intervention. It provides an extremely high degree of accuracy, and provides repeatability of measurements within a minuscule tolerance of error. The method determines the evolute of the surface automatically, deterministically, and repeatably via orthogonal reflection by ascertaining the evolute of the surface's figure along multiple diameters of the surface.

Embodiments of the present disclosure relate to a measuring method and device for measuring surface defects of a cambered optical element, which belongs to the field of photoelectric detection technology. The device includes a sensor measuring head, a rotatable workpiece table, an automatic sampling device, and a spraying device. The sensor measuring head includes an illumination sub-system and a line scan imaging sub-system, the illumination sub-system provides an illumination of high uniformity and high brightness for a surface of a sample to be detected, the rotatable workpiece table and the imaging sub-system are configured for performing a ring belt scanning and a high resolution scatter imaging to the defects on an optical surface region. The automatic sampling device is used as a mechanical arm in an automatic production for automatically clamping optical elements; the spraying device is activated once foreign matters such as dust and impurities are detected on the surface, so as to accurately remove false defects such as dust and impurities on the surface of the piece to be detected. Embodiments of the present disclosure effectively solve the problem that the surface defect detection of the large caliber optical element is difficult and the efficiency thereof is low, and can quickly measure surface defects of a large caliber planar, spherical and cambered optical element.

An optical inspection device includes: a wafer support unit configured to support a wafer in which a plurality of Fabry-Perot interference filter portions are formed, each of the plurality of filter portions in which a distance between the first mirror portion and the second mirror portion facing each other varies by an electrostatic force, the wafer support unit configured to support the wafer such that a direction in which the first mirror portion and the second mirror portion face each other follows along a reference line; a light emission unit configured to emit light to be incident on each of the plurality of filter portions along the reference line; and a light detection unit configured to detect light transmitted through each of the plurality of filter portions along the reference line. The wafer support unit has a light passage region that allows light to pass along the reference line.

A system and method for advanced charge control of a light beam is provided. The system comprising a laser source comprising a laser diode for emitting a beam and a beam homogenizer to homogenize the emitted beam. The system and methods further comprise a beam shaper configured to shape the emitted beam using an anamorphic prism group and a driver configured to direct the shaped beam to a specified position on a wafer, wherein the laser source, the beam shaper, and the driver are coaxially aligned.

To provide a reflected light measurement device capable of efficiently performing disconnection inspection on an optical connector, and a plurality of optical fibers. The reflected light measurement device 1 includes a laser light source 2, a beam splitter 3 that branches measurement laser light L into measurement laser light L1 to be transmitted and reference laser light L2 to be reflected, a reference mirror 4 including an optical path length varying mechanism capable of adjusting an optical path length of the reference laser light L2, an optical path length switching unit 5, and switches the optical path length of the reference laser light L2 to a plurality of fixed lengths, and a photometer 6 that receives measurement laser light L1 reflected at defect sites D1 and D2 such as disconnection inside connectors C1 and C2, and reference laser light L2 reflected by the reference mirror 4.

A flaw detecting apparatus and a method for a plane mirror based on line scanning and ring band stitching are provided. The flaw detecting apparatus comprises: a line scanning detector, an annular illumination source, a rotary table rotatable about a Z axis, a translation table translatable along an X axis and a processor. By translating and rotating the plane mirror to be detected, an entire surface of the plane mirror to be detected can be detected by the line scanning detector, and the flaw of the entire plane mirror to be detected is obtained by a ring band stitching method. The method of line scanning and ring band stitching reduces the imaging distortion, the intermediate data amount, the difficulty in the distortion correction and difficulty in stitching, and improves the detection speed and the detection quality.

Embodiments of the present disclosure relate to a measuring method and device for measuring surface defects of a cambered optical element, which belongs to the field of photoelectric detection technology. The device includes a sensor measuring head, a rotatable workpiece table, an automatic sampling device, and a spraying device. The sensor measuring head includes an illumination sub-system and a line scan imaging sub-system, the illumination sub-system provides an illumination of high uniformity and high brightness for a surface of a sample to be detected, the rotatable workpiece table and the imaging sub-system are configured for performing a ring belt scanning and a high resolution scatter imaging to the defects on an optical surface region. The automatic sampling device is used as a mechanical arm in an automatic production for automatically clamping optical elements; the spraying device is activated once foreign matters such as dust and impurities are detected on the surface, so as to accurately remove false defects such as dust and impurities on the surface of the piece to be detected. Embodiments of the present disclosure effectively solve the problem that the surface defect detection of the large caliber optical element is difficult and the efficiency thereof is low, and can quickly measure surface defects of a large caliber planar, spherical and cambered optical element.

The invention relates to a method for determining the thickness of a contaminating layer and/or the type of a contaminating material on a surface (7) in an optical system, in particular on a surface (7) in an EUV lithography system, comprising: irradiating the surface (7) on which plasmonic nanoparticles (8a,b) are formed with measurement radiation (10), detecting the measurement radiation (10a) scattered at the plasmonic nanoparticles (8a,b), and determining the thickness of the contaminating layer and/or the type of the contaminating material on the basis of the detected measurement radiation (10a). The invention also relates to an optical element (1) for reflecting EUV radiation (4), and to an EUV lithography system.