Provided are an optical element, including a plurality of optically anisotropic layers, each of which has an in-plane alignment pattern in which orientations of optical axes derived from a liquid crystal compound change continuously and rotationally along at least one in-plane direction, in a thickness direction, in which the optically anisotropic layers each have regions where lengths over which the orientations of the optical axes rotate by 180 in the one direction are different from each other, and at least one of the plurality of optically anisotropic layers is an inclined optically anisotropic layer having a region where a plurality of pairs of bright lines and dark lines in a cross-sectional image are present and the pairs of the bright lines and the dark lines are inclined at inclination angles which are different from each other with respect to a normal line of an interface of the optically anisotropic layer.

The disclosure relates to a grating and a radiation imaging device. The grating comprises a plurality of stacked grating elements. The grating elements are stacked to form a grid. The grating element comprises a first sheet and a second sheet having two parallel planes. The second sheet is stacked at the first sheet in a length direction of the first sheet. The first sheet is almost impervious to radiation. The present disclosure stacks the sheets having different specifications together to form the grating with uniform grating slits, such that there is no limitation on the thickness of the grating and the grating can be used along with high-energy radiations.

A diffractive optical element prevents degradation of the optical performance of the element due to moisture absorption of the resin layers from taking place and also can prevent cracks of the resin layers and peeling of the resin layers along the interface thereof from taking place in a hot environment or in a cold environment. The diffractive optical element comprises a first layer and a second layer sequentially laid on a substrate, a diffraction grating being formed at the interface of the first layer and the second layer, the height d of the diffraction grating, the average film thickness t1 of the first layer and the average film thickness t2 of the second layer satisfying the relationship requirements expressed by the expressions of 1.1dt150 m and 30 mt2(400 mt1d).

A system for an extreme ultraviolet (EUV) light source includes a light-generation system configured to emit one or more light beams onto a beam path; one or more optical amplifiers, each of the one or more amplifiers including a gain medium on the beam path, each gain medium being configured to amplify the one or more light beams to produce one or more amplified light beams; and one or more diffractive optical elements on the beam path, where each of the one or more diffractive optical elements has a plurality of focal lengths, and each focal length of the diffractive optical element is associated with a particular polarization state.

An EUV collector transfers EUV radiation from an EUV radiation source into an illumination far field. The collector has a normal mirror collector subunit including a mirror for normal incidence, and a grazing mirror collector subunit including a mirror for grazing incidence. The arrangement of the collector subunits is such that an intensity distribution of the EUV radiation over the far field results which is composed of an inner normal mirror intensity distribution, generated by reflection at least also at the normal mirror collector subunit, and of an outer grazing mirror intensity distribution, generated by reflection at least also at the grazing mirror collector subunit. The intensity distribution, at least over a section of the far field which is greater than 40% of the total far field, deviates by less than 20% from an average intensity in the section of the far field.

A membrane transmissive to EUV radiation, which may be used as a pellicle or spectral filter in a lithographic apparatus. The membrane includes one or more high doped regions wherein the membrane is doped with a dopant concentration greater than 10.sup.17 cm.sup.3, and one or more regions with low (or no) doping. The membrane may have a main substrate having low doping and one or more additional layers, wherein the high doped regions are comprised within some or all of the additional layers.

The present invention relates to a method for producing an image of a target using radiation and a diffraction grating and apparatus for x-ray imaging. The method comprises directing a beam of radiation to the target to produce a modified beam through interaction with the target, directing the modified beam to an diffraction grating to produce an interference pattern, detecting the interference pattern using a detector, and forming an image of the target using the interference pattern measured. According to the invention, the diffraction grating is modified n the plane of the grating during the imaging so that at least two interference patterns are detected using the detector different configurations of the diffraction grating. Further, the image of the target using the at least two interference patterns measured. The invention provides a simple configuration, less radiation exposure and/or better image quality then conventional imaging methods.

A lithographic apparatus for patterning a beam of radiation and projecting it onto a substrate, comprising at least two spectral purity filters configured to reduce the intensity of radiation in the beam of radiation in at least one undesirable range of radiation wavelength, wherein the two spectral purity filters are provided with different radiation filtering structures from each other.

A plasma-generated EUV light source uses an EUV-diffracting collection mirror to channel spectrally pure in-band radiation through an intermediate-focus aperture and through EUV illumination optics. Out-of-band radiation is either undiffracted by the collection mirror or is diffractively scattered away from the aperture. The undiffracted portion, plus plasma-emitted radiation that does not intercept the collection mirror, can be efficiently recycled back to the plasma via retroreflecting mirrors, cat's-eye reflectors, or corner-cube reflectors, to enhance generation of in-band EUV radiation by the plasma.

A lithographic apparatus for patterning a beam of radiation and projecting it onto a substrate, comprising at least two spectral purity filters configured to reduce the intensity of radiation in the beam of radiation in at least one undesirable range of radiation wavelength, wherein the two spectral purity filters are provided with different radiation filtering structures from each other.