A beam guide guides a laser beam on a device for extreme ultraviolet lithography. The beam guide has a scraper mirror for coupling out laser radiation and a positioning device for positioning the scraper mirror in a positioning plane defined by first and second positioning axes. The positioning device contains first and second positioning units assigned to the first and second positioning axes, respectively. The first positioning unit has a first linear guide and a first positioning drive. By the first positioning drive, the scraper mirror is moved together with the mirror-side guide element of the first linear guide relative to the mirror-remote guide element of the first linear guide along the first positioning axis into a target position. The second positioning unit has a second linear guide and a second positioning drive, the second linear guide has a mirror-side guide element and a mirror-remote guide element.

A beam guide guides a laser beam on a device for extreme ultraviolet lithography. The beam guide has a scraper mirror for coupling out laser radiation and a positioning device for positioning the scraper mirror in a positioning plane defined by first and second positioning axes. The positioning device contains first and second positioning units assigned to the first and second positioning axes, respectively. The first positioning unit has a first linear guide and a first positioning drive. By the first positioning drive, the scraper mirror is moved together with the mirror-side guide element of the first linear guide relative to the mirror-remote guide element of the first linear guide along the first positioning axis into a target position. The second positioning unit has a second linear guide and a second positioning drive, the second linear guide has a mirror-side guide element and a mirror-remote guide element.

Disclosed is an optical kit for forming an optical system including an external resonator of a laser light source that outputs laser light, the optical kit including: a base including a main surface; a light source holding part provided on the main surface for holding the laser light source; and a holding part provided on the main surface for holding the optical system, wherein the holding part has a reflector holding part for holding the corner reflector, a first opening member holding part for holding the first opening member, and a second opening member holding part for holding the second opening member, and wherein the first opening member holding part is positioned closer to the reflector holding part than an emission surface of the laser light of the laser light source held by the light source holding part.

Disclosed is an optical kit for forming an optical system including an external resonator of a laser light source that outputs laser light, the optical kit including: a base including a main surface; a light source holding part provided on the main surface for holding the laser light source; and a holding part provided on the main surface for holding the optical system, wherein the holding part has a reflector holding part for holding the corner reflector, a first opening member holding part for holding the first opening member, and a second opening member holding part for holding the second opening member, and wherein the first opening member holding part is positioned closer to the reflector holding part than an emission surface of the laser light of the laser light source held by the light source holding part.

A gas laser device includes a laser oscillator outputting laser light, and a laser amplifier amplifying the laser light and outputting the amplified laser light. The laser amplifier includes a discharge chamber accommodating electrodes for causing discharge, an input coupling optical system causing part of the laser light to be transmitted toward the discharge chamber, and an output coupling optical system configuring an optical resonator together with the input coupling optical system and causing part of the laser light transmitted through the input coupling optical system and the discharge chamber to be transmitted therethrough and output the amplified laser light. A first focal point of the input coupling optical system and a second focal point of the output coupling optical system in a first direction being perpendicular to a direction of the discharge coincides at a position between the input coupling optical system and the output coupling optical system.

An integrated optical linewidth reduction system based on optical feedback and a low-speed electronic control loop to control the optical feedback. Light is tapped and reflected back to the laser with an amplitude, phase or both amplitude and phase adjustment such that the linewidth of the laser is lower than the free-running laser linewidth. The amplitude of the feedback signal may be controlled using an optical attenuator. The phase of the feedback signal may be controlled using a phase shifter. The amplitude of the optical feedback may be monitored by means of a filter and a photodetector, or just a photodetector. The amplitude and/or phase of the optical feedback is monitored by means of a frequency/phase noise discriminator. The phase shifter can be an endless phase shifter.

An integrated optical linewidth reduction system based on optical feedback and a low-speed electronic control loop to control the optical feedback. Light is tapped and reflected back to the laser with an amplitude, phase or both amplitude and phase adjustment such that the linewidth of the laser is lower than the free-running laser linewidth. The amplitude of the feedback signal may be controlled using an optical attenuator. The phase of the feedback signal may be controlled using a phase shifter. The amplitude of the optical feedback may be monitored by means of a filter and a photodetector, or just a photodetector. The amplitude and/or phase of the optical feedback is monitored by means of a frequency/phase noise discriminator. The phase shifter can be an endless phase shifter.