An optical arrangement, in particular a projection
exposure apparatus (1) for EUV
lithography, includes: a housing (2) that encloses an
interior space (15); at least one, in particular reflective, optical element (4 to 10, 12, 14.1 to 14.6) that is arranged in the housing (2); at least one vacuum
generating unit (3) for generating a vacuum in the
interior space (15) of the housing (2); and at least one vacuum housing (18, 18.1 to 18.10) that is arranged in the
interior space (15) of the housing (2) and that encloses at least the
optical surface (17, 17.1, 17.2) of the optical element (4 to 10, 12, 14.1 to 14.5), wherein a
contamination reduction unit is associated with the vacuum housing (18.1 to 18.10), which
contamination reduction unit reduces the
partial pressure of contaminating substances, in particular of water and / or hydrocarbons, at least in close proximity to the
optical surface (17, 17.1, 17.2) in relation to the
partial pressure of the contaminating substances in the interior space (15).