A system includes: an optical source including a plurality of optical oscillators; a spectral analysis apparatus; and a controller. Each optical oscillator is configured to produce a light beam. The controller is configured to: determine, based on data from the spectral analysis apparatus, whether the spectral property of the light beam of one of the optical oscillators is different than the spectral property of the light beam of at least another of the plurality of optical oscillators. If the spectral property of the light beam of the first one of the optical oscillators is different than the spectral property of the light beam of another of the optical oscillators, the controller is configured to adjust the spectral property of the light beam of the first one of the optical oscillators or of the light beam of at least one other of the optical oscillators.

There may be provided a laser unit including a display configured to display one or both of electric power consumed by the laser unit and electric energy consumed by the laser unit.

A laser chamber for a discharge excited gas laser apparatus may include: a first discharge electrode disposed in the laser chamber; a second discharge electrode disposed to face the first discharge electrode in the laser chamber; a fan configured to flow laser gas between the first discharge electrode and the second discharge electrode; a first insulating member disposed upstream and downstream of a laser gas flow from the first discharge electrode; a metallic damper member disposed upstream of the laser gas flow from the second discharge electrode; and a second insulating member disposed downstream of the laser gas flow from the second discharge electrode.

A discharge chamber for a deep ultraviolet (DUV) light source includes a housing; and a first electrode and a second electrode in the housing, the first electrode and the second electrode being separated from each other to form a discharge region between the first electrode and the second electrode, the discharge region being configured to receive a gain medium including at least one noble gas and a halogen gas. At least one of the first electrode and the second electrode includes a metal alloy including more than 33% and less than 50% zinc by weight.

A discharge chamber for a deep ultraviolet (DUV) light source includes a housing; and a first electrode and a second electrode in the housing, the first electrode and the second electrode being separated from each other to form a discharge region between the first electrode and the second electrode, the discharge region being configured to receive a gain medium including at least one noble gas and a halogen gas. At least one of the first electrode and the second electrode includes a metal alloy including more than 33% and less than 50% zinc by weight.

A discharge chamber for a deep ultraviolet (DUV) light source includes a housing; and a first electrode and a second electrode in the housing, the first electrode and the second electrode being separated from each other to form a discharge region between the first electrode and the second electrode, the discharge region being configured to receive a gain medium including at least one noble gas and a halogen gas. At least one of the first electrode and the second electrode includes a metal alloy including more than 33% and less than 50% zinc by weight.

A laser gas regeneration system for an excimer laser includes a first pipe capable of supplying a laser chamber with a first laser gas, a second pipe capable of supplying the laser chamber with a second laser gas having a halogen gas concentration higher than that of the first laser gas, a third pipe allowing a gas exhausted from the laser chamber to pass therethrough, a gas refiner that refines the gas having passed through the third pipe, a branch that causes the refined gas to divide and flow into a fourth pipe and a fifth pipe, a first regenerated gas supplier that supplies the first pipe with a gas having divided and flowed into the fourth pipe, and a second regenerated gas supplier that adds a halogen gas to a gas having divided and flowed into the fifth pipe and supplies the second pipe with the halogen-added gas.

A discharge chamber for a deep ultraviolet (DUV) light source includes a housing; and a first electrode and a second electrode in the housing, the first electrode and the second electrode being separated from each other to form a discharge region between the first electrode and the second electrode, the discharge region being configured to receive a gain medium including at least one noble gas and a halogen gas. At least one of the first electrode and the second electrode includes a metal alloy including more than 33% and less than 50% zinc by weight.

A laser gas regeneration system for an excimer laser includes a first pipe capable of supplying a laser chamber with a first laser gas, a second pipe capable of supplying the laser chamber with a second laser gas having a halogen gas concentration higher than that of the first laser gas, a third pipe allowing a gas exhausted from the laser chamber to pass therethrough, a gas refiner that refines the gas having passed through the third pipe, a branch that causes the refined gas to divide and flow into a fourth pipe and a fifth pipe, a first regenerated gas supplier that supplies the first pipe with a gas having divided and flowed into the fourth pipe, and a second regenerated gas supplier that adds a halogen gas to a gas having divided and flowed into the fifth pipe and supplies the second pipe with the halogen-added gas.

There may be provided a laser unit including a display configured to display one or both of electric power consumed by the laser unit and electric energy consumed by the laser unit.