Abstract: The invention relates to extreme ultraviolet “EUV” radiation generating systems that include a vacuum chamber where a target material can be positioned at a target position for generation of EUV radiation, and a beam guiding chamber for guiding a laser beam from a driver laser device towards the target position. The EUV radiation generating apparatus includes an intermediate chamber which is arranged between the vacuum chamber and the beam guiding chamber, a first window which seals the intermediate chamber in a gas-tight manner for entry of the laser beam from the beam guiding chamber and a second window which seals the intermediate chamber in a gas-tight manner for exit of the laser beam into the vacuum chamber. The invention also relates to a method for operating the EUV radiation generating apparatus.

Abstract: A device for amplifying a laser beam is provided. The device includes at least one amplifier chamber in which a laser-active material is provided, at least one transmitting optical member delimiting the amplifier chamber and being arranged at a tilt angle, ?, with respect to a plane oriented perpendicularly with respect to an optical axis of the laser beam, and at least one detection unit. The laser beam is reflected by the transmitting optical member into a back reflected laser beam, and the detection unit is arranged such that it detects the back reflected laser beam.

Abstract: A gas laser includes discharge tubes connected to together by corner housings, each corner housing including a first cooling channel configured to allow flow of a first coolant. A heat exchanger circuit includes a plurality of second cooling channels configured to allow flow of a second coolant. Each second cooling channel is operable to cool laser gas prior to the laser gas entering into one of the corner housings. The gas laser further includes a temperature control device, in which the temperature control device is selected from the group consisting of a laser gas cooling device, a coolant temperature control assembly, and combinations thereof. The temperature control device is operable to maintain a temperature difference of less than approximately 5 K between the first coolant flowing through the first cooling channel of the corner housing and the laser gas entering into the corner housing.