In a laser system according to a viewpoint of the present disclosure, a first amplifier amplifies first pulsed laser light outputted from a first semiconductor laser system into second pulsed laser light, a wavelength conversion system converts the second pulsed laser light in terms of wavelength into third pulsed laser light, and an excimer amplifier amplifies the third pulsed laser light. The first semiconductor laser system includes a first current controller that controls current flowing through a first semiconductor laser in such a way that first laser light outputted from the first semiconductor laser is caused to undergo chirping and a first semiconductor optical amplifier that amplifies the first laser light into pulsed light. The laser system includes a control section that controls the amount of chirping performed on the first pulsed laser light in such a way that excimer laser light having a target spectral linewidth is achieved.

A gas laser apparatus may include a chamber filled with a laser gas; a window provided in the chamber and through which a laser beam passes; an optical path tube connected to the chamber to surround a position of the window in the chamber; a heated gas supply port configured to supply a heated purge gas into a closed space including a space in the optical path tube; and an exhaust port configured to exhaust a gas in the closed space.

A copper electrode material comprising Cu and unavoidable impurities, wherein the content of the unavoidable impurities is 1 ppm by mass or less and the average crystal grain diameter is 100 μm or less. A copper-containing electrode material having improved corrosion resistance is provided by the copper electrode material.

A laser system includes: A. a solid-state laser apparatus configured to output a pulse laser beam having light intensity distribution in a Gaussian shape that is rotationally symmetric about an optical path axis; B. an amplifier including a pair of discharge electrodes and configured to amplify the pulse laser beam in a discharge space between the pair of discharge electrodes; and C. a conversion optical system configured to convert the light intensity distribution of the pulse laser beam output from the amplifier into a top hat shape in each of a discharge direction of the pair of discharge electrodes and a direction orthogonal to the discharge direction.

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.

An optical isolator according to an aspect of the present disclosure includes a first polarizer through which incident light transmits, a Faraday rotator configured to rotate the polarization direction of the light, and a second polarizer through which the light transmits. The Faraday rotator includes a calcium fluoride crystal. When a, b, and c axes are the [001], [100], and [010] crystallographic axes, respectively, and x, y, and z axes are obtained by rotating the three axes by a first angle of 40° to 50° about the c axis and by a second angle of 45° to 75° about the b axis rotated by the first angle, the z axis is parallel to the propagation direction of the light, and the calcium fluoride crystal is disposed such that the transmission axis of the first polarizer and the x axis have an angle difference of 0° to 45°.

An ultraviolet laser apparatus includes an oscillation-stage laser, an amplifier that amplifies the pulse laser light, and an optical isolator. The optical isolator includes a first Faraday rotator that rotates the polarization direction of the pulse laser light output from the oscillation-stage laser by a first angle in a first rotation direction, a first polarizer so disposed to transmit the pulse laser light that exits out of the first Faraday rotator at normalized transmittance greater than or equal to 0.9, a second Faraday rotator that rotates the polarization direction of the pulse laser light passing through the first polarizer by a second angle in the opposite direction to the first rotation direction, and a second polarizer so disposed to transmit the pulse laser light that exits out of the second Faraday rotator at the normalized transmittance greater than or equal to 0.9.

An optical isolator includes a first polarizer arranged such that a transmission axis thereof is set to cause a normalized transmittance with respect to incident light having a wavelength of ultraviolet and linear polarization to be 0.9 or more, a Faraday rotator using a Faraday material configured to rotate a polarization direction of light having transmitted through the first polarizer in a first rotation direction by a first rotation amount by a magnetic field and rotate the polarization direction in a second rotation direction opposite to the first rotation direction by a second rotation amount by optical activity or birefringence, and a second polarizer arranged such that a transmission axis thereof is set to cause a normalized transmittance with respect to the incident light having transmitted through the Faraday rotator to be 0.9 or more.

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 line narrowing module includes a prism including an entrance side surface that light enters, an exit side surface from which the light is emitted, and a bottom surface, and configured to wavelength-disperse the light having entered the entrance side surface and to emit the light from the exit side surface; a holder portion having a stationary surface on which the bottom surface of the prism is secured; a rotary mechanism portion including a rotary stage on which the holder portion is secured, the rotary stage being configured to rotate the prism around an axis perpendicular to a dispersion plane of the light emitted from the prism; a drive unit configured to rotate the rotary stage; and a grating configured to reflect the light emitted from the prism, centroids of the prism, the holder portion, and the rotary stage being located on the axis.