Apparatus for providing optical radiation (9), which apparatus comprises; a first seed source (1) for providing first seeding radiation (11); a second seed source (2) for providing second seeding radiation (12); a coupler (3) connected to the first seed source (1) and the second seed source (2) for coupling the first seeding radiation (11) and the second seeding radiation (12) together; and at least one amplifier (4) for amplifying the first seeding radiation (11) and the second seeding radiation (12).

In a laser system according to an aspect of the present disclosure, the following components are disposed: a first container that accommodates a first heater and a first crystal holder holding a first nonlinear crystal and includes a first light incident window via which laser light is incident and a first light exit window via which the laser light exits; a second container that accommodates a second heater and a second crystal holder holding a second nonlinear crystal and includes a second light incident window via which the laser light is incident and a second light exit window via which the laser light exits; and a stage that holds the first and second containers. A controller controls the stage to move the first nonlinear crystal away from the optical path of the laser light and inserts the second nonlinear crystal into the optical path of the laser light.

A wavelength conversion apparatus according to an aspect of the present disclosure is a wavelength conversion apparatus that performs wavelength conversion of light through a non-linear crystal and including a first non-linear crystal, a container in which the first non-linear crystal is housed, a crystal holding member provided inside the container for fixing the first non-linear crystal, a first window provided to the container for guiding light to the first non-linear crystal from outside of the container, a second window provided to the container for guiding light output from the first non-linear crystal to outside of the container, a first heater provided inside the container for heating the first non-linear crystal, a battery that supplies electric power to the first heater, and a first controller that controls electric power supply to the first heater.

A laser beam irradiation unit of a laser processing apparatus includes a first pulsed laser oscillator that oscillates a pulsed laser having a wavelength of 9 to 11 μm and a pulse width of 5 ns or less, a CO.sub.2 amplifier that amplifies a pulsed laser beam emitted from the first pulsed laser oscillator, and a condenser that focuses the pulsed laser beam amplified by the CO.sub.2 amplifier on a workpiece held on the chuck table.

A laser apparatus according to an aspect of the present disclosure includes a plurality of semiconductor lasers, a plurality of optical switches disposed in the optical paths of the plurality of respective semiconductor lasers, a wavelength conversion system configured to convert pulsed beams outputted from the plurality of optical switches in terms of wavelength to generate wavelength-converted beams, an ArF excimer laser amplifier configured to amplify the wavelength-converted beams, and a controller configured to control the operations of the plurality of semiconductor lasers and the plurality of optical switches, and the plurality of semiconductor lasers are each configured to output a laser beam so produced that wavelengths of the wavelength-converted beams are wavelengths at which the ArF excimer laser amplifier performs amplification and differ from the optical absorption lines of oxygen.

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.

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.

Embodiments of the disclosure provide an apparatus for emitting laser light and a system and method for detecting laser light returned from an object. The system includes a transmitter and a receiver. The transmitter includes one or more laser sources, at least one of the laser sources configured to provide a respective native laser beam having a wavelength above 1,100 nm. The transmitter also includes a wavelength converter configured to receive the native laser beams provided by the laser sources and convert the native laser beams into a converted laser beam having a wavelength below 1,100 nm. The transmitter further includes a scanner configured to emit the converted laser beam to the object in a first direction. The receiver is configured to detect a returned laser beam having a wavelength below 1,100 nm and returned from the object in a second direction.

A low-repetition-rate (10-Hz), picosecond (ps) optical parametric generator (OPG) system produces higher energy output levels in a more robust and reliable system than previously available. A picosecond OPG stage is seeded at an idler wavelength with a high-power diode laser and its output at ˜566 nm is amplified in a pulsed dye amplifier (PDA) stage having two dye cells, resulting in signal enhancement by more than three orders of magnitude. The nearly transform-limited beam at ˜566 nm has a pulse width of ˜170 ps with an overall output of ˜2.3 mJ/pulse. A spatial filter between the OPG and PDA stages and a pinhole between the two dye cells improve high output beam quality and enhances coarse and fine wavelength tuning capability.

A fiber laser apparatus that generates invisible laser light using an amplification optical fiber having a core and that propagates a fundamental mode and a low-order mode is provided. The fiber laser apparatus includes a visible laser light source that generates visible laser light, an introducing section that introduces the visible laser light generated by the visible laser light source into a core of the amplification optical fiber, a cladding light attenuating section that attenuates light which has propagated through a cladding of the amplification optical fiber, at a subsequent stage of the amplification optical fiber, and a drive unit that drives the visible laser light source to emit the visible laser light through a core of the output optical fiber in a case of performing alignment of an irradiation position of the invisible laser light with respect to a workpiece.