A laser system includes a random phase plate in an optical path between a solid-state laser device and an excimer amplifier. Cells of a predetermined shape are periodically arranged on the plate, each cell being a minimum unit region of an irregular pattern, regions of depressions or projections in units of the cells being randomly arranged. When a traveling direction of a laser beam is a Z direction, a discharge direction is a V direction, a direction orthogonal to the V and Z directions is an H direction, an in-plane direction of the plate corresponding to the V direction is a first direction, an in-plane direction of the plate corresponding to the H direction is a second direction, lengths of the cell are d1 in the first direction and d2 in the second direction, an aspect ratio of the cell defined by d2/d1 is 1.2 or more.

A laser system according to one aspect of the present disclosure includes a first solid-state laser device, a wavelength conversion system, an excimer amplifier, and a control unit. The first solid-state laser device includes a first multiple semiconductor laser system, a first semiconductor optical amplifier, and a first fiber amplifier. The first multiple semiconductor laser system includes a plurality of first semiconductor lasers configured to perform continuous wave oscillation in a single longitudinal mode with different wavelengths, a first spectrum monitor, and a first beam combiner. The control unit controls an oscillation wavelength and light intensity of each line of a first multiline spectrum generated by the first semiconductor lasers to obtain an excimer laser beam having at least a target center wavelength or a target spectral line width instructed by an external device.

A laser system including: A. a laser apparatus configured to output a pulse laser beam; B. an optical pulse stretcher including a delay optical path for expanding a pulse width of the pulse laser beam; and C. a phase optical element included in the delay optical path and having a function of spatially and randomly shifting a phase of the pulse laser beam. The phase optical element includes a plurality of types of cells providing different amounts of phase shift to the pulse laser beam and arranged irregularly in any direction.

A gas purification system may include: a circulation gas pipe in which a second end is connected at a first position to a second pipe through which gas is supplied from a gas supply source; a booster pump; a gas purification unit; a first tank in the circulation gas pipe; a first valve positioned between the gas supply source and the first position, the first valve having an open position and a closed position; and a second valve positioned between the first tank and the second end, the second valve having an open position and a closed position, the second valve configured to be in the closed position when the first valve is in the open position.

A laser device, including multiple laser modules, includes a plurality of drive power units that drive the laser modules, a plurality of output detection units that detect laser outputs from the laser modules, and output detected values as first output signals, a coupled output detection unit that detects a total laser output after coupling of a plurality of the laser outputs, and outputs a detected value as a second output signal, a computing unit that sets multiple output correction factors for correspondingly controlling the laser modules using the plurality of first output signals and the second output signal, and a control unit that controls the plurality of drive power units using the multiple output correction factors. The multiple output correction factors are each set to allow the total laser output to be maintained at a constant value.

An argon fluoride (ArF) laser system for inertial nuclear fusion energy production with lower required laser energy than other laser drivers. An Argon fluoride laser system uniformly illuminates a spherical capsule comprising an outer ablator wall surrounding an inner shell comprising the fusion fuel. The laser beams are adjusted spectrally to achieve a bandwidth of up to 12 THz and a coherence time as low as 80 femtoseconds that in combination with the short wavelength (193 nm) suppress laser plasma instabilities. Uniform spherical acceleration causes the inner shell of the target capsule to form a spherical assembly of compressed fuel surrounding a hot spot that has sufficient temperature, density and size to ignite and initiate a thermonuclear burn.

A spectral feature selection apparatus includes a dispersive optical element arranged to interact with a pulsed light beam; three or more refractive optical elements arranged in a path of the pulsed light beam between the dispersive optical element and a pulsed optical source; and one or more actuation systems, each actuation system associated with a refractive optical element and configured to rotate the associated refractive optical element to thereby adjust a spectral feature of the pulsed light beam. At least one of the actuation systems is a rapid actuation system that includes a rapid actuator configured to rotate its associated refractive optical element about a rotation axis. The rapid actuator includes a rotary stepper motor having a rotation shaft that rotates about a shaft axis that is parallel with the rotation axis of the associated refractive optical element.

In a method, energy is supplied to a first gas discharge chamber of a first stage until a pulsed amplified light beam is output from the first stage and directed toward a second stage. While the energy is supplied to the first gas discharge chamber: a value of an operating parameter of the first gas discharge chamber is measured; it is determined whether to adjust an operating characteristic of the first gas discharge chamber based on the measured value; and, the operating characteristic of the first gas discharge chamber is adjusted if it is determined that the operating characteristic of the first gas discharge chamber should be adjusted. After it is determined that the operating characteristic of the first gas discharge chamber no longer should be adjusted, then an adjustment procedure is applied to an operating characteristic of a second gas discharge chamber of the second stage.

A laser apparatus of the present disclosure includes: a master oscillator configured to emit a laser beam; a laser amplifier disposed on an optical path of the laser beam; a propagation optical system disposed on an optical path between the laser amplifier and a target supplied into an EUV chamber in which EUV light is generated; and a polarization isolator disposed on an optical path between the laser amplifier and the propagation optical system. The polarization isolator includes: a polarizer configured to emit, selecting from the laser beam incident on the polarizer, a laser beam linearly polarized in a predetermined polarization direction; and a reflection retarder disposed on an optical path between the polarizer and the propagation optical system to convert, through reflection, the laser beam linearly polarized in the predetermined polarization direction into an elliptically polarized laser beam having retardation that reduces retardation occurring at the propagation optical system.

A laser device, including multiple laser modules, includes a plurality of drive power units that drive the laser modules, a plurality of output detection units that detect laser outputs from the laser modules, and output detected values as first output signals, a coupled output detection unit that detects a total laser output after coupling of a plurality of the laser outputs, and outputs a detected value as a second output signal, a computing unit that sets multiple output correction factors for correspondingly controlling the laser modules using the plurality of first output signals and the second output signal, and a control unit that controls the plurality of drive power units using the multiple output correction factors. The multiple output correction factors are each set to allow the total laser output to be maintained at a constant value.