A laser device includes a first actuator configured to adjust an oscillation wavelength of pulse laser light; a second actuator configured to adjust a spectral line width of the pulse laser light; and a processor configured to determine a target spectral line width by reading data specifying a number of irradiation pulses of the pulse laser light with which one location of an irradiation receiving object is irradiated and a difference between a shortest wavelength and a longest wavelength, control the second actuator based on the target spectral line width, and control the first actuator so that the oscillation wavelength periodically changes every number of the irradiation pulses between the shortest wavelength and the longest wavelength.

A line narrowing module includes an enclosure, a prism which is disposed in an internal space of the enclosure and through which light passes, a mounter which is disposed in the internal space and on which the prism is mounted, a fixing unit which is disposed in the internal space and fixes the prism to the mounter, and a light blocking member. The light blocking member is disposed in the internal space and blocks scattered light in the internal space, the scattered light produced from the light and traveling to the fixing unit.

A line narrowing gas laser device includes a line narrowing device, an output coupling mirror, a laser chamber arranged on an optical path of an optical resonator, a first holder which supports the output coupling mirror, a second holder which supports the first holder to be rotatable about a rotation axis of the first holder, and an adjustment device supported by the second holder and being in contact with the first holder to rotate the first holder about the rotation axis. The line narrowing device has a characteristic of changing, into a first direction, beam pointing of laser light output toward the output coupling mirror when temperature inside the line narrowing device rises. The second holder and the adjustment device rotate the first holder in a direction in which a change in the first direction in the beam pointing of the laser light is suppressed by thermal expansion.

A laser apparatus including an optical element made of a CaF.sub.2 crystal and configured to transmit an ultraviolet laser beam obliquely incident on one surface of the optical element, the electric field axis of the P-polarized component of the laser beam propagating through the optical element coinciding with one axis contained in <111> of the CaF.sub.2 crystal, with the P-polarized component defined with respect to the one surface. A method for manufacturing an optical element, the method including causing a seed CaF.sub.2 crystal to undergo crystal growth along one axis contained in <111> to form an ingot, setting a cutting axis to be an axis inclining by an angle within 14.18±5° with respect to the crystal growth direction toward the direction of another axis contained in <111>, which differs from the crystal growth direction, and cutting the ingot along a plane perpendicular to the cutting axis.

A WDM seed beam source for a fiber laser amplifier system that includes a number of master oscillators that generate seed beams at different wavelengths and a spectral multiplexer that multiplexes all of the seed beams onto a single fiber. An EOM modulates the combined seed beams on the single fiber and a spectral demultiplexer then separates the modulated seed beams into their constituent wavelengths on separate fibers before the seed beams are amplified and spectrally combined. The fiber laser amplifier system includes a separate fiber amplifier that amplifies the separated seed beams, an emitter array that directs the amplified beams into free space, beam collimating optics that focuses the uncombined beams, and an SBC grating responsive to the collimated uncombined beams that spatially combines the collimated uncombined beams.

An apparatus for emitting pulsed electromagnetic laser radiation includes a laser gain element; an optical arrangement defining a laser resonator and arranged to re-direct radiation emitted by the gain element along a beam path back onto the gain element, the optical arrangement comprising an output coupler configured to couple a portion of the radiation in the laser resonator out of the laser resonator; and, a pump arrangement configured to pump the laser gain element. The optical arrangement includes a mode locker placed in the laser resonator in the beam path, and a birefringent element placed in the laser resonator in the beam path.

A method for generating femtosecond vortex beams with high spatial intensity contrast, where a noncollinearly pumped HG beam femtosecond laser generates femtosecond HG beam and a cylindrical lens mode converter converts the femtosecond HG beam to femtosecond LG vortex beam. The HG beam femtosecond laser comprises a pump source, a gain medium, a saturable absorption mirror as mode-locker, and an output coupler with a noncollinear angle between the laser beam and the pump beam in the gain medium, which enables the laser to generate pure, order-tunable femtosecond HG beams. Femtosecond vortex beams obtained after the cylindrical lens converter have high-intensity-contrast, and are topological charge-tunable.

A semiconductor-laser-device assembly includes a mode-locked semiconductor-laser-element assembly including a mode-locked semiconductor laser element, and a dispersion compensation optical system, on which laser light emitted from the mode-locked semiconductor laser element is incident and from which the laser light is emitted; and a semiconductor optical amplifier having a layered structure body including a group III-V nitride-based semiconductor layer, the semiconductor optical amplifier configured to amplify the laser light emitted from the mode-locked semiconductor-laser-element assembly.

A grating for line-narrowing a laser beam that is outputted from a laser apparatus at a wavelength in a vacuum ultraviolet region may include: a grating substrate; a first aluminum metal film formed above the grating substrate, the first aluminum metal film having grooves in a surface thereof; and a first protective film formed by an ALD method above the first aluminum metal film.

A laser chamber including a first space and a second space in communication with the first space may include: a first discharge electrode disposed in the first space; a second discharge electrode disposed in the first space to face the first discharge electrode; a fan disposed in the first space and configured to flow laser gas between the first discharge electrode and the second discharge electrode; a peaking condenser disposed in the second space; and an electrical insulating member configured to partition the first space and the second space from one another, and disposed to allow the laser gas to pass through between the first space and the second space.