A multi-stage thulium-doped (Tm-doped) fiber amplifiers (TDFA) is based on the use of single-clad Tm-doped optical fiber and includes a wavelength conditioning element to compensate for the nonuniform spectral response of the initial stage(s) prior to providing power boosting in the output stage. The wavelength conditioning element, which may comprise a gain shaping filter, exhibits a wavelength-dependent response that flattens the gain profile and output power distribution of the amplified signal prior to reaching the output stage of the multi-stage TDFA. The inclusion of the wavelength conditioning element allows the operating bandwidth of the amplifier to be extended so as to encompass a large portion of the eye-safe 2 μm wavelength region.

Method and systems are disclosed for generating amplified output laser pulses with individually predefined pulse energies at individually predefined times at an output by providing a pulse sequence of input laser pulses having the same pulse energy and the same temporal pulse interval smaller than the temporal pulse interval between two adjacent output laser pulses, selecting the input laser pulses that arrive at the output at or about the predefined times, amplifying the selected input laser pulses with an optical amplifier, wherein at least one sacrificial laser pulse is inserted into the pulse sequence of the selected input laser pulses before the subsequent one of the two successive input laser pulses to be amplified, and reducing the pulse energies of the amplified input laser pulses to predefined pulse energies by time-controlled partial decoupling depending on their pulse intervals from the corresponding immediately preceding amplified input or sacrificial laser pulse.

Systems and methods include a radiation source configured to generate a first waveform, a first separator configured to separate the first waveform into linearly polarized second and third waveforms, a first modulator configured to modulate at least one of a phase and a polarization of the second waveform to generate a fourth waveform, a second modulator configured to modulate at least one of a phase and a polarization of the third waveform to generate a fifth waveform, a first combiner configured to combine the fourth and fifth waveforms to generate a sixth waveform, an amplifier configured to amplify the sixth waveform to generate a seventh waveform, a second separator configured to separate the seventh waveform into a plurality of amplified waveforms, and beam directing optics configured to direct the plurality of amplified waveforms to form an output waveform at a target location.

A laser beam delivery apparatus of an extreme ultra violet light source may include a high power seed module configured to generate a laser beam, a power amplifier configured to amplify the laser beam generated by the high power seed module, a beam transfer module configured to collect and move the laser beam amplified by the power amplifier, a final focusing assembly optical platform configured to adjust focus of the laser beam collected and moved by the beam transfer module, and a focusing unit configured to focus the laser beam with the focus adjusted by the final focusing assembly optical platform to a target droplet. The power amplifier may include a position adjuster configured to adjust a position of the laser beam. The position adjuster may include a refraction plate having a flat surface. The power amplifier may include a pointing adjuster, which may include a mirror.

A system includes at least one controller configured to determine an optical phase modulation pattern for suppression of stimulated Brillouin scattering (SBS) in a combined beam that emerges off a diffractive grating in a spectral beam combining (SBC) system and maximization of an output power of the combined beam. The system also includes multiple master oscillators configured to generate multiple beams in the SBC system. The system also includes multiple phase modulators configured to phase modulate the multiple beams according to the determined optical phase modulation pattern. The system also includes multiple fiber amplifier chains configured to receive the phase modulated beams and output the beams from the master oscillators to multiple delivery fibers for subsequent combining into the combined beam at the diffractive grating.

A method of pulse shaping using spectral filtering, positive chirp, and self-phase modulation to control the accumulated higher-order phase terms of the spectral phase. This pulse shaping method has particular advantage in fiber chirped pulse amplification (FCPA) systems, where there are two effects: (1) an offsetting of the fourth order phase via nonlinear phase accumulation, allowing for a higher Strehl ratio (i.e., a cleaner pulse), higher peak power pulse and (2) enabling power scaling to higher pulse energies without the increased nonlinear phase accumulation leading to pulse breakup. This technique can be used both in a passive system with no amplification to clean up an existing pulse, and in an amplifier system to enable higher performance operation (shorter pulses, cleaner pulses, higher energy pulses).

A line field optical coherence tomography (OCT) system and an absorption spectrometer system employing a tunable or swept laser architecture. The laser is a cat's-eye configuration with a preferably transmissive tilt tuned interference thin film filter.

A hybrid coherent beam combining (CBC) and spectral beam combining (SBC) fiber laser amplifier system including a beam shaper array assembly and a beam source that provides a plurality of beams having a low fill factor profile. The assembly includes an input beam shaper array having a plurality of rectilinear input cells positioned adjacent to each other that are shaped to cause the beam to expand as it propagates away from the input array to be converted from the low fill factor profile to a high fill factor profile. The assembly further includes an output beam shaper array having a plurality of output cells positioned adjacent to each other that are shaped to cause the beam to stop expanding so that the output array provides a plurality of adjacent beams with minimal overlap and a minimal gap between the beams.

A system and method for fabricating an optical element. The method includes welding an array of fibers to the optical element, measuring an angle error and a position error of each fiber, calculating a correction for each fiber for the angle error and the position error and correcting the angle and position of each fiber using the calculated corrections.

The ultra-short pulse chirped pulse amplification (CPA) laser system and method of operating CPA laser system include outputting nearly transform limited (TL) pulses by a mode locked laser. The system and method further include temporarily stretching the TL pulses by a first Bragg grating providing thus each stretched pulse with a chirp which is further compensated for in a second Bragg grating operating as as a compressor. The laser system and method further include a pulse shaping unit measuring a spectral phase across the recompressed pulse and further adjusting the deviation of the measured spectral phase from that of the TL pulse by generating a corrective signal. The corrective signal is applied to the array of actuators coupled to respective segments of one of the BGs which are selectively actuated to induce the desired phase change, with the one BG thus operating as both stretcher/compressor and pulse shaper.