Abstract: A method of cleaning at least one surface of an optical device disposed in a vacuum chamber, which is at least partially contaminated by atoms and/or ions of metalloid and/or metal introduced by a radiation source generating, in particular, extreme ultraviolet radiation and/or 10 soft X-rays is described. In order to achieve a longer service life for the optical device (14), the method is designed such that a temperature prevailing on the surface (10) and/or a pressure in the vacuum chamber (12) is adjusted in such a way that the atoms and/or ions (20) hitting the surface (10) can move upon it.

Abstract: The invention describes a method of manufacturing a filter for retaining a substance originating from a radiation source, which filter comprises a thin layer that is transparent to extreme ultraviolet and/or soft X-ray radiation and which may be used inter alia in a device for EUV lithography. It is proposed that the filter (10) is high-temperature-resistant so as to render possible its use in particular for high-power radiation sources.

Abstract: The present invention relates to highly dense translucent and transparent aluminium oxide components for applications, e.g. in the lighting industry, where a fine crystal size has to be obtained and stabilized for use at temperatures of 800° C. or more. Disclosed are high-strength polycrystalline alumina products which include 0.001-0.5 weight-% ZrO2 stabilizing a fine crystal size <2 ?m or, preferably, <1 ?m if used at temperatures of 800° C. or more. The microstructure exhibits an extremely high relative density enabling a high real in-line transmission >30% measured over an angular aperture of at most 0.5° at a sample thickness of 0.8 mm and with a monochromatic wavelength of light?, preferably, of 645 run.