A method and a device for generating a series of laser pulses in a laser device, particularly single and multiple bursts of pulses with a minimum temporal distance between the pulses in a single burst in the picosecond domain. The device includes at least a master oscillator and a regenerative amplifier. The method includes steps of injecting a laser pulse from the master oscillator into the regenerative amplifier, amplifying injected pulse burst during multiple round-trips in an optical cavity of the regenerative amplifier, ejecting amplified pulse burst from the cavity of the regenerative amplifier. The injection step involves applying a first intermediate voltage to an optical switch for a time span, during which pulses from the oscillator are injected into the amplifier, forming a burst of injected seed pulses, which are further amplified in the amplification step, in which the optical switch voltage is set to a locking voltage.

Disclosed is a laser system that includes a femtosecond oscillator, a regenerative amplifier for chirped pulse amplification of femtosecond laser pulses, and a compressor. The regenerative amplifier includes a plurality of positive Group Delay Dispersion (GDD) mirrors disposed within a cavity of the regenerative amplifier. The compressor receives amplified laser pulses from the regenerative amplifier.

Disclosed is a laser system including a source, for generating a source signal, and an optical amplifier system. The laser system includes a pulse selection or variation device configured to select or vary the source signal so as to form a main signal composed of one or more light pulses. The main signal is temporally variable in terms of rhythm and/or amplitude. The laser system is configured to inject the main signal and a secondary signal into the optical amplifier system. The secondary signal is varied on the basis of the temporal variation in terms of rhythm and/or amplitude of the main signal so as to stabilize the power stored in the optical amplifier system in a time-dependent manner, and the laser system is configured to spatially separate the amplified main signal from the amplified secondary signal.

A phase control system for controlling the relative phase (φ) 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 method and system for combining two or more optical fields is disclosed. A first continuous-wave high powered output field generated by a solid-state master laser is injected into a first solid state optical amplifier to produce a single output field from the laser system that exhibits a high phase-coherence with the output field of the master laser. The power of the output field equals the sum of powers of the master laser and that generated by the first optical amplifier, while exhibiting similar beams characteristics to that produced by the output field of the master laser i.e. it exhibits low noise, in a single transverse and longitudinal mode Gaussian beam, and has a single polarisation. The laser system is highly scalable in that N optical amplifiers may be located in series with the master laser to provide a single low noise, high power output field.

The present invention relates to a laser system and a method of generating a defined spatial mode-shaped laser beam using an unstable laser resonator layout. The laser system for mode shaping of a laser beam within an unstable optical resonator layout comprising an active medium, characterized in that, the active media comprises a pumped area, wherein the gain distribution is generated by an optical pump beam's spatially intensity profile.

In a preferred embodiment, the system may further comprise an end-pumped layout to deliver the spatially shaped optical pump beam to the active medium; and/or an active element and/or a passive element for modifying the resonator losses; and/or means of output coupling of a laser beam from said unstable resonator layout.

The system according to the present invention is suitable to deliver a top-hat beam profile.

A laser device may include a light source configured to emit a laser beam in burst operation, an optical sensor configured to acquire a cross sectional image of the laser beam during a certain period for every certain cycle, an image processor configured to receive an input of an image signal of the cross sectional image outputted from the optical sensor and output beam relating information about the laser beam, a beam traveling direction adjuster configured to adjust a traveling direction of the laser beam, and a controller configured to control the beam traveling direction adjuster based on the beam relating information when at least a part of a period in which the optical sensor acquires the cross sectional image is overlapped with a period in which the light source emits a laser beam.

An extreme ultraviolet light (EUV) generation system is configured to improve conversion efficiency of energy of a laser system to EUV energy by improving the efficiency of plasma generation. The EUV generation system includes a target generation unit configured to output a target toward a plasma generation region in a chamber. The laser system is configured to generate a first pre-pulse laser beam, a second pre-pulse laser beam, and a main pulse laser beam so that the target is irradiated with the first pre-pulse laser beam, the second pre-pulse laser beam, and the main pulse laser beam in this order. In addition, the EUV generation system includes a controller configured to control the laser system so that a fluence of the second pre-pulse laser beam is equal to or higher than 1 J/cm.sup.2 and equal to or lower than a fluence of the main pulse laser beam.

Disclosed is a laser system that incudes a chirped fiber oscillator, a laser amplifier, and a compressor. The laser amplifier includes a laser Faraday isolator. The fiber oscillator output is directly coupled to the laser Faraday isolator.

Disclosed is a laser system that includes a femtosecond oscillator, a regenerative amplifier for chirped pulse amplification of femtosecond laser pulses, and a compressor. The regenerative amplifier includes a plurality of positive Group Delay Dispersion (GDD) mirrors disposed within a cavity of the regenerative amplifier. The compressor receives amplified laser pulses from the regenerative amplifier.