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.

An optical element for a deep-ultraviolet light source includes a crystalline substrate; a coating on an exterior surface of the crystalline substrate, the coating having a thickness along a direction that extends away from the exterior surface; and a structure on and/or in the coating, the structure including a plurality of features that extend away from the crystalline substrate along the direction. The features include an amorphous dielectric material and are arranged such that an index of refraction of the structure varies along the direction.

An excimer laser apparatus according to the present disclosure includes a chamber configured to accommodate a laser gas and a pair of electrodes and generate pulse-oscillating laser light when the gas pressure of the laser gas is controlled in accordance with voltage applied between the pair of electrodes, a power supply configured to apply the voltage between the pair of electrodes, and a controller to which a target value of the spectral linewidth of the laser light is inputted, the controller configured to correct the voltage used to control the gas pressure, when the target value changes from a first target value to a second target value, based on a first function having the second target value as a parameter and control the gas pressure in accordance with the corrected voltage.

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.

A laser chamber apparatus may include a pipe, an inner electrode extending along a longitudinal direction of the pipe and disposed in a through hole in the pipe, an outer electrode including a contact plate extending along the longitudinal direction of the pipe and being in contact with an outer circumferential surface of the pipe and a ladder section formed of bar members each having one end connected to the contact plate and juxtaposed along a longitudinal direction of the contact plate, and a leaf spring extending along the longitudinal direction of the pipe and configured to press the outer electrode against the pipe. The leaf spring may include leaf spring pieces separated by slits, and the leaf spring pieces may each include a bent section bent along the edge and are configured to press the bar members in a position shifted from the bent sections toward the edge.

A device includes a laser source, an amplifier, an optical sensor and a spectrometer. The laser source is configured to produce a seed laser beam. The amplifier includes gain medium and a discharging unit. The discharging unit is configured to pump the gain medium for amplifying power of the seed laser beam. The optical sensor is coupled to the amplifier and configured for sensing an optical emission generated in the amplifier while the gain medium is discharging. The spectrometer is coupled with the optical sensor and configured to measure a spectrum of the optical emission.

A device includes a laser source, an amplifier, an optical sensor and a spectrometer. The laser source is configured to produce a seed laser beam. The amplifier includes gain medium and a discharging unit. The discharging unit is configured to pump the gain medium for amplifying power of the seed laser beam. The optical sensor is coupled to the amplifier and configured for sensing an optical emission generated in the amplifier while the gain medium is discharging. The spectrometer is coupled with the optical sensor and configured to measure a spectrum of the optical emission.

A laser crystallization method includes exciting gas medium in an airtight container to generate laser beams; amplifying the laser beams by reflecting the laser beams between a high reflection mirror and a low reflection mirror respectively disposed facing opposite end portions of the airtight container, wherein a first transparent window and a second transparent window are fixed to respective end portions of the airtight container, and outputting the amplified laser beams; and disposing a cleaning mirror in a path of the laser beams that have propagated through the second transparent window.

A laser crystallization method includes exciting gas medium in an airtight container to generate laser beams; amplifying the laser beams by reflecting the laser beams between a high reflection mirror and a low reflection mirror respectively disposed facing opposite end portions of the airtight container, wherein a first transparent window and a second transparent window are fixed to respective end portions of the airtight container, and outputting the amplified laser beams; and disposing a cleaning mirror in a path of the laser beams that have propagated through the second transparent window.