A wavelength measuring device configured to detect a wavelength of ultraviolet laser light outputted from a laser resonator with at least one etalon, the wavelength measuring device includes: a first housing having an interior space being sealed and accommodating the etalon, an input window through which the ultraviolet laser light enters to the first housing, the input window being provided at a first opening of the first housing, a first sealing member configured to seal a gap between a rim part of the input window and a circumferential portion of the first opening, a shielding film provided between the rim part of the input window and the first sealing member and configured to shield the first sealing member from the ultraviolet laser light coming from the input window, and a diffusing element provided outside of the first housing and configured to diffuse the ultraviolet laser light before being incident on the input window.

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 laser gas regenerating apparatus regenerates a discharged gas discharged from at least one ArF excimer laser apparatus and supplies the regenerated gas to the at least one ArF excimer laser apparatus connected to a first laser gas supply source that supplies a first laser gas and to a second laser gas supply source that supplies a second laser gas. The laser gas regenerating apparatus includes a data obtaining unit that obtains data on a supply amount of the second laser gas supplied to the at least one ArF excimer laser apparatus; a xenon adding unit that adds, to the regenerated gas, a third laser gas; and a control unit that controls, based on the supply amount, an addition amount of the third laser gas by the xenon adding unit.

A laser chamber of an excimer laser apparatus includes a container including a first member and a second member and configured to accommodate a laser gas in the container and a seal member disposed between two seal surfaces facing each other, a seal surface of the first member and a seal surface of the second member. A laser-gas-side surface of the seal member is made of fluorine-based rubber, and an atmosphere-side surface of the seal member is formed of a film configured to suppress atmosphere transmission.

A gas chamber supply system includes a gas source configured to fluidly connect to a gas chamber and to supply a gas mixture to the gas chamber, the gas source including: a pre-prepared gas supply including a gas mixture, the gas mixture including a plurality of gas components and lacking a halogen; a recycled gas supply including the gas mixture; and a fluid flow switch connected to the pre-prepared gas supply and to the recycled gas supply. The gas chamber supply also includes a control system configured to: determine if the relative concentration between the gas components within the recycled gas supply is within an acceptable range; and provide a signal to the fluid flow switch to thereby select one of the pre-prepared gas supply and the recycled gas supply to as the gas source based on the determination.

An apparatus includes: a gas maintenance system having a gas supply system fluidly connected to one or more gas discharge chambers; a detection apparatus fluidly connected to each gas discharge chamber; and a control system connected to the gas maintenance system and the detection apparatus. The detection apparatus includes: a vessel defining a reaction cavity that houses a metal oxide and is fluidly connected to the gas discharge chamber for receiving mixed gas including fluorine from the gas discharge chamber in the reaction cavity, the vessel enabling a reaction between the fluorine of the received mixed gas and the metal oxide to form a new gas mixture including oxygen; and an oxygen sensor fluidly connected to the new gas mixture to sense an amount of oxygen within the new gas mixture. The control system is configured to estimate a concentration of fluorine in the received mixed gas.

A wavelength error for each pulse in a first subset of pulses emitted from an optical source is determined, the wavelength error being the difference between a wavelength for a particular pulse and a target wavelength; a pulse-by-pulse correction signal is determined based on the determined wavelength error, the pulse-by-pulse correction signal including a correction signal associated with each pulse in the first subset of pulses; and a correction based on the determined pulse-by-pulse correction signal is applied to each pulse in a second subset of pulses emitted from the optical source, where applying a correction to a pulse in the second subset of pulses reduces the wavelength error of the pulse in the second subset of pulses.

Methods, devices, and apparatus for generating plasma or laser pulses by radio frequency (RF) excitation pulses are provided. In one aspect, a method includes specifying radio frequency (RF) excitation pulses at least partially as a function of a preceding RF excitation of a medium and outputting a signal to a RF pulse generator, the signal configured to cause the RF pulse generator to generate the specified RF excitation pulses for exciting the medium to generate plasma or laser pulses. The RF excitation pulses is specified to become more strongly reduced in energy when a remaining excitation of the medium by the preceding RF excitation is higher.

Methods, devices, and apparatus for generating plasma or laser pulses by radio frequency (RF) excitation pulses are provided. In one aspect, a method includes specifying radio frequency (RF) excitation pulses at least partially as a function of a preceding RF excitation of a medium and outputting a signal to a RF pulse generator, the signal configured to cause the RF pulse generator to generate the specified RF excitation pulses for exciting the medium to generate plasma or laser pulses. The RF excitation pulses is specified to become more strongly reduced in energy when a remaining excitation of the medium by the preceding RF excitation is higher.

A polarisation and mode selection technique for a gas waveguide laser is described in which a surface of the waveguide is formed to be substantially dielectric with a localised metallic region therein. The metallic region provides linear polarisation while the dielectric surface provides for low order mode selection. Embodiments are described to channel and planar waveguides with various resonator configurations. Ranges are provided for the size and location of the metallic region on the waveguide surface.