A system for generating extreme ultraviolet light, in which a target material inside a chamber is irradiated with a laser beam to be turned into plasma, includes a first laser apparatus configured to output a first laser beam, a second laser apparatus configured to output a pedestal and a second laser beam, and a controller connected to the first and second laser apparatuses and configured to cause the first laser beam to be outputted first, the pedestal to be outputted after the first laser beam, and the second laser beam having higher energy than the pedestal to be outputted after the pedestal.

Direct diode-pumped Ti:sapphire laser amplifiers use fiber-coupled laser diodes as pump beam sources. The pump beam may be polarized or non-polarized. Light at wavelengths below 527 nm may be used in cryogenic configurations. Multiple diode outputs may be polarization or spectrally combined.

A laser apparatus may include: a quantum cascade laser outputting, based on a supplied current, laser light at an oscillation start timing when a first delay time elapses from a current rising timing of the supplied current: an amplifier disposed in a laser light optical path, and selectively amplifying light of a predetermined wavelength to output the amplified laser light to a chamber including a plasma generation region into which a target is fed; and a laser controller controlling a third delay time, from an output timing of a laser output instruction to the current rising timing, to cause a laser light wavelength to be equal to the predetermined wavelength at an aimed timing when a second delay time elapses from the oscillation start timing, based on oscillation parameters including the first delay time, a supplied current waveform, and a device temperature of the quantum cascade laser.

Direct diode-pumped Ti:sapphire laser amplifiers use fiber-coupled laser diodes as pump beam sources. The pump beam may be polarized or non-polarized. Light at wavelengths below 527 nm may be used in cryogenic configurations. Multiple diode outputs may be polarization or spectrally combined.

Techniques for controlling an optical system include accessing a measured value of a property of a particular pulse of a pulsed light beam emitted from the optical system, the property being related to an amount of coherence of the light beam; comparing the measured value of the property of the light beam to a target value of the property; determining whether to generate a control signal based on the comparison; and if a control signal is generated based on the comparison, adjusting the amount of coherence in the light beam by modifying an aspect of the optical system based on the control signal to reduce an amount of coherence of a pulse that is subsequent to the particular pulse.

The invention describes classes of robust fiber laser systems usable as pulse sources for Nd: or Yb: based regenerative amplifiers intended for industrial settings. The invention modifies adapts and incorporates several recent advances in FCPA systems to use as the input source for this new class of regenerative amplifier.

A divided-pulse laser regeneration amplification apparatus includes: a signal light coupling component including a first half-wave plate, a first polarization beam splitter, a first Faraday rotator and a second half-wave plate placed in sequence; and a divided-pulse laser regeneration amplification component including a second polarization beam splitter and a third reflector, the second polarization beam splitter is adjacent to the second half-wave plate and is in a same column as the third reflector and the second half-wave plate; a first quarter-wave plate, a Pockels cell and a first reflector are successively arranged on a first side of the second polarization beam splitter, and a third half-wave plate, a first pulse polarization separation component and a first non-linear pulse amplification component are successively arranged on a second side of the second polarization beam splitter.

Laser-apparatus includes a fiber-MOPA arranged to deliver amplified seed optical pulses having a wavelength of about 1043 nanometers to a multi-pass ytterbium-doped yttrium aluminum garnet solid-state optical amplifier for further amplification.

A phase control system for controlling the relative phase () of two laser beams of a laser system, which are to be coherently combined, is disclosed that enables providing a phase-controlled sum laser beam. An optical system of the phase control system includes a beam input for receiving a measuring portion of two collinear coherent laser beams, which are superimposed to form a sum laser beam, and provides measuring beams or measuring beam regions, which are used with associated photodetectors for outputting photodetector signals. For determining the relative phase from the photodetector signals, the phase control system has an evaluation device and a delay device for being inserted into the beam path of at least one of the two laser beams. The optical system is configured such that the measuring beams or measuring beam regions are related to different phase offsets.

A high-average-power OPCPA amplifier comprising a pump laser, a signal laser, and a nonlinear crystal amplifier. The pump laser includes an Nd:YVO.sub.4 laser oscillator-regenerative amplifier, an Nd:YAG boost amplifier, a frequency-doubling convertor, and a frequency-tripling convertor. The signal laser includes a supercontinuum generator, a pulse stretcher, and a pulse compressor. The chirped signal and the pump laser is intersected with a noncollinear angle of 3.0 to 4.0 in the nonlinear crystal amplifier and the temperature of the crystal amplifier is set at higher than 320K for simultaneous temperature- and wavelength-insensitive phase-matching.