An EUV collector mirror has a reflection surface (16) to reflect usable EUV light which impinges on the reflection surface (16) from a source region (17) to a subsequent EUV optics. The reflection surface (16) carries a pump light grating structure (19) configured to retroreflect pump light (22) which impinges upon the pump light grating structure (19) from the source region (17) back to the source region (17). The pump light (22) has a wavelength deviating from the wavelength of the usable EUV light. Such EUV collector mirror enables a high conversion efficiency between the energy of pump light of a laser discharged produced plasma (LDPP) EUV light source on the one hand and the resulting usable EUV energy on the other.

Optical elements that efficiently propagate x-ray radiation over a desired energy range and reject radiation outside the desired energy range are presented herein. In one aspect, one or more optical elements of an x-ray based system include an integrated optical filter including one or more material layers that absorb radiation having energy outside the desired energy band. In general, the integrated filter improves the optical performance of an x-ray based system by suppressing reflectivity within infrared (IR), visible (vis), ultraviolet (UV), extreme ultraviolet (EUV) portions of the spectrum, or any other undesired wavelength region. In a further aspect, one or more diffusion barrier layers prevent degradation of the integrated optical filter, prevent diffusion between the integrated optical filter and other material layers, or both. In some embodiments, the thickness of one or more material layers of an integrated optical filter vary over the spatial area of the filter.

A reflective optical element (1) for reflecting light having at least one wavelength in an EUV wavelength range has an optically effective region configured for reflecting the light incident on a surface (2) of the optically effective region. The reflective optical element (1) has an edge (4) forming at least part of a boundary of an edge-free surface (3) of the reflective optical element (1), wherein the edge-free surface (3) includes the surface (2) of the optically effective region. The edge (4) has a chamfer and/or a rounding. Also disclosed is a method for adapting a geometry of at least one surface region of a component of an optical arrangement, for example of a reflective optical element (1).

An X-ray fluorescence analyzer including an X-ray tube for emitting incident X-rays in the direction of a first optical axis. A slurry handling unit is configured to maintain a constant distance between a sample of slurry and the X-ray tube. A first crystal diffractor is located in a first direction from the slurry handling unit. The first crystal diffractor includes a first crystal and a first radiation detector configured to detect fluorescent X-rays diffracted by the first crystal at a first energy resolution. A second crystal diffractor is located in a second direction from the slurry handling unit. The second crystal diffractor includes a second crystal and a second radiation detector configured to detect fluorescent X-rays diffracted by the second crystal at a second energy resolution. The first crystal is a pyrolytic graphite crystal, the second crystal is of a material other than pyrolytic graphite, and the first and second crystal diffractors are configured to direct to their respective radiation detectors characteristic fluorescent radiation of a same element.

A reflector comprising a hollow body having an interior surface defining a passage through the hollow body, the interior surface having at least one optical surface part configured to reflect radiation and a supporter surface part, wherein the optical surface part has a predetermined optical power and the supporter surface part does not have the predetermined optical power. The reflector is made by providing an axially symmetric mandrel; shaping a part of the circumferential surface of the mandrel to form at least one inverse optical surface part that is not rotationally symmetric about the axis of the mandrel; forming a reflector body around the mandrel; and releasing the reflector body from the mandrel whereby the reflector body has an optical surface defined by the inverse optical surface part and a supporter surface part defined by the rest of the outer surface of the mandrel.

A mask blank glass substrate having a maximum value of a circularly averaged power spectral density of 1,000 nm.sup.4 or less at a spatial frequency of 0.1 μm.sup.−1 or more and 20 μm.sup.−1 or less, the maximum value being obtained by measuring a surface morphology of a region of 10 μm×10 μm with an atomic force microscope.

A dispersive element is provided with a dispersive crystal for spectrally dispersing X-rays, a first support layer supporting the dispersive crystal, and a second support layer supporting the first support layer. The first support layer is greater in a thermal expansion coefficient than the dispersive crystal. The second support layer is smaller in a thermal expansion coefficient than the first support layer and is greater in rigidity than the first support layer.

A grating structure is provided with arc-shaped stabilizing bridging structures on the lamellae that allow for bending the grating to account for stresses and deformations induced by the bending process to obtain a more stable curved grating structure more efficiently.

A mirror having a mirror substrate (12, 32, 52), a reflection layer stack (21, 41, 61) reflecting electromagnetic radiation having an operating wavelength that is incident on the optical effective surface (11, 31, 51), and at least one piezoelectric layer (16, 36, 56), arranged between the substrate and the reflection layer stack and to which an electric field producing a locally variable deformation is applied. A first electrode arrangement (20, 40, 60) situated on the side of the piezoelectric layer faces the reflection layer stack, and a second electrode arrangement (14, 34, 54) is situated on the side of the piezoelectric layer facing the mirror substrate. Optionally, a bracing layer (98) is provided, which limits sinking of the piezoelectric layer (96) into the mirror substrate (92) when an electric field is applied, in comparison with an analogous construction lacking the bracing layer, thereby increasing the piezoelectric layer's effective deflection.

An X-ray fluorescence analyzer includes an X-ray tube for emitting incident X-rays in the direction of a first optical axis. A slurry handling unit is configured to maintain a constant distance between a sample of slurry and the X-ray tube. A first crystal diffractor is located in a first direction from the slurry handling unit and configured to separate a predefined first wavelength range from fluorescent X-rays that propagate into the first direction. The first crystal diffractor is configured to direct the fluorescent X-rays in the separated predefined first wavelength range to a first radiation detector. The first crystal diffractor includes a pyrolytic graphite crystal that has a diffractive surface, which is a simply connected surface. The first radiation detector is a solid-state semiconductor detector.