A beam transformer for transforming an input laser beam into a transformed laser beam for use in laser systems for line illumination of an object includes a transparent planar optical element that has a front surface and a back surface, which extend substantially parallel to one another. The optical element has an entrance area and an exit area, and a plurality of reflective surfaces for beam deflection. The beam transformer further includes a cooling device provided at least on the front surface or the back surface of the optical element.

A beam reverser module for an optical power amplifier of a laser arrangement comprises at least one reflecting surface for receiving an incoming laser beam propagating in a first direction and reflecting the incoming laser beam into a second direction different from the first direction, wherein the at least one reflecting surface is a highly reflecting surface of at least one mirror.

The disclosure relates to a beam-forming unit for forming a laser beam and focusing the laser beam onto a workpiece. The unit includes a movable component, an immovable component, and a cooling system configured for movement of a cooling medium to actively cool the movable component. The cooling system has-a cooling water circuit on the immovable component configured for water cooling of both the immovable component and the cooling medium.

Optical element (1) comprising a first window (21) and a second window (22), wherein the first window (21) is connected to the second window (22) by an elastic membrane (41) such that the first window (21), the second window (22) and the membrane (41) enclose a deformable, sealed volume (42), which is filled with a fluid, wherein at least one first actuator (51) is arranged to tilt the first window (21) with respect to the second window (22) around a first tilting axis (81) in a first direction, wherein the first actuator (51) comprises a Shape Memory Alloy and has the shape of a wire.

Disclosed are an optical system, in particular for microlithography, and a method for operating an optical system. According to one disclosed aspect, the optical system includes at least one mirror (100, 500, 600) having an optical effective surface (101, 501, 601) and a mirror substrate (110, 510, 610), wherein at least one cooling channel (115, 515, 615) in which a cooling fluid is configured to flow is arranged in the mirror substrate, for dissipating heat that is generated in the mirror substrate due to absorption of electromagnetic radiation incident from a light source on the optical effective surface, and a unit (135, 535, 635) to adjust the temperature and/or the flow rate of the cooling fluid either dependent on a measured quantity that characterizes the thermal load in the mirror substrate or dependent on an estimated/expected thermal load in the mirror substrate for a given power of the light source.

The disclosure provides a method that includes filling a cavity in a substrate with a second material, wherein the substrate includes a first material. The method also includes using galvanic and/or chemical deposition of a third material to apply an overcoating to a first surface of the substrate in a region of the cavity. The method further includes removing the second material from the cavity. In addition, the method includes, before or after removing the second material from the cavity, applying a reflective layer to the overcoating. The disclosure also provides related optical articles and systems.

The cooling device of the present disclosure has a thermally conductive base that is thermally connected to a heat-generating section, a heat pipe section embedded in the base, and a fin section that has a plurality of fins and is connected to the base in a way that the fin section covers the heat pipe section.

A mirror array having a total surface extending perpendicularly to a surface normal, comprises a multiplicity of mirror elements each having a reflection surface and at least one degree of freedom of displacement, wherein the totality of the mirror elements form a parqueting of a total reflection surface of the mirror array, and wherein the mirror array is embodied modularly as a tile element in such a way that the parqueting of the total reflection surface can be extended by a tiling of a plurality of such mirror arrays.

An optical path changing device includes: a reflective member that reflects a light beam incident thereto, in a predetermined reflection direction; and a housing holding the reflective member. The housing has a first surface and a second surface with the reflective member interposed therebetween in a direction orthogonal to the reflection direction. The first surface and the second surface have openings, respectively, and a cooling gas is circulated from the opening in the first surface to the opening in the second surface.

A projection lens of an EUV-lithographic projection exposure system with at least two reflective optical elements each comprising a body and a reflective surface for projecting an object field on a reticle onto an image field on a substrate if the projection lens is exposed with an exposure power of EUV light, wherein the bodies of at least two reflective optical elements comprise a material with a temperature dependent coefficient of thermal expansion which is zero at respective zero cross temperatures, and wherein the absolute value of the difference between the zero cross temperatures is more than 6K.