A pulsed third-harmonic laser system includes a pulsed laser, an extra-cavity nonlinear crystal, and an intracavity nonlinear crystal. The pulsed laser generates fundamental laser pulses and couples out a portion of each fundamental laser pulse out of the laser resonator to undergo second-harmonic-generation in the extra-cavity nonlinear crystal. Resulting second-harmonic laser pulses are directed back into the laser resonator and mixes with the fundamental laser pulses in the intracavity nonlinear crystal to generate third-harmonic laser pulses. The pulsed third-harmonic laser system thus maintains a non-zero output coupling efficiency regardless of the efficiency of the second-harmonic-generation stage, while the third-harmonic-generation stage benefits from the intracavity power of the fundamental laser pulses.

A laser for emitting simultaneously a first and second laser lights having respectively first and second wavelength differing from each other. The laser comprises: an optical resonator defining a first optical path and a second optical path, the first laser light travelling along the first optical path and the second laser light travelling along the second optical path; a modulated gain element inserted in the optical resonator for amplifying the first and second laser lights as the first and second laser lights propagate in the optical resonator respectively along the first and second optical paths, the modulated gain element having a variable gain modulated with a modulation period, round trip times of the first and second laser lights along respectively the first and second optical paths being respective integer multiples of the modulation period; and an output port for releasing the first and second laser lights from the optical resonator.

The present invention relates to a system for modulating laser pulses by means of an electro-optical modulator which is operated by means of a pulsed modulation voltage. A voltage converter mounted upstream of the modulator converts a pulsed modulated switching voltage at an output voltage level to the modulation voltage that is higher than the output voltage level. The invention further relates to a method for modulating laser pulses.

A single mode fiber pulsed oscillator includes an all normal dispersion ring cavity provided with a mode-locking fiber loop component and a giant chirp generating fiber component. The mode-locking fiber loop component is configured with a hybrid of NOLM and NALM configurations which is operative to induce a first phase acquisition of a spectrally narrow pulse due to SPM. The giant chirp generating fiber loop component is configured to induce the additional phase acquisition to the pulse broadened in the mode-locking fiber component so as to generate a pulse with a giant chirp. The fiber loop components each include a fiber amplifier and a coil of fiber. The amplifiers each are configured with an active fiber provided with a core which supports multiple transverse mode in a range of wavelength except for the desired wavelength at which the core is configured to support a single fundamental mode.

The invention is a passively mode-locked ultrashort pulse fiber laser for generating ultrashort laser pulses, including a resonator in a figure-of-eight configuration, wherein the resonator has a main ring and a secondary ring optically coupled thereto designed as a non-linear Sagnac interferometer, and wherein the main ring and the secondary ring are constructed of polarization-maintaining optical fibers, and the main ring and/or secondary ring have a fiber section designed as a laser-active medium, wherein the laser-active medium is optically pumped through an externally-coupled pump light source which is also comprised, wherein the ultrashort pulse fiber laser is developed in that a separate optical unit is provided in the resonator as a dispersion compensation unit for compensating a group delay dispersion of the ultrashort laser pulses.

Operating an optical frequency comb assembly includes operating an optical frequency comb source to generate laser light constituting an optical frequency comb and introducing the laser light into a common light path and seeding at least one branch light path by the laser light from the common light path, the branch light path comprising at least one optical element. For the branch light path, a phase difference of a first frequency mode ν.sub.1 of the optical frequency comb is determined between laser light coupled out at a reference point within the frequency comb assembly upstream of the at least one optical element and laser light coupled out at a measurement point provided in the branch light path downstream of the at least one optical element. Phase correction for the laser light from the branch light path is based on a deviation of the determined phase difference from a target value.

The present disclosure relates to a method and an apparatus for generating a laser pulse sequence for application to a predetermined target tissue. Means are provided for setting a cumulative fluence F.sub.s of the laser pulse sequence. Means are provided for determining a duration of the laser pulse sequence as a function of the cumulative fluence F.sub.s such that the predetermined target tissue is heated to a final temperature that is within a predetermined range.

A pulse analysis system or method includes a frequency filter that receives an ultrafast pulse under test and disperses the pulse under test over a frequency range. The frequency filter separates the pulse under test into component frequency slices and provides the frequency slices to a detector coupled to a digitizer, which processes the digitized signal and collects a sonogram characteristic of the pulse under test. The frequency slices are arranged to overlap. Ptychography is performed on the sonogram to obtain characteristics of the pulse under test.

A method and a system for measurement of high laser field intensity, the method comprising tight focusing a non-Gaussian azimuthally polarized laser mode beam to a focusing spot, measuring a spectral line shape of a selected ionization state induced by a longitudinal oscillating magnetic field created by the tight focusing in the focusing spot; and determining the laser intensity from the spectral line shape. The system comprises a laser source of a peak power in a range between 100 terawatt and 10 petawatt; a converter unit; a tight focusing optics; and spectral measurement means; wherein the converter unit polarizes a main laser beam from the laser source into a non-Gaussian azimuthally polarized laser mode beam; the tight focusing optics focuses the azimuthally polarized laser mode beam to a focusing spot, yielding a longitudinal oscillating magnetic field of an intensity proportional to the laser intensity, the spectral measurement means measuring a line shape of a selected ionization state induced by the longitudinal oscillating magnetic field in focusing spot.

A MOPA laser system that includes a seed laser configured to output pulsed laser light, an amplifier configured to receive and amplify the pulsed laser light emitted by the seed laser; and a pump laser configured to deliver a pump laser beam to both the seed laser and the amplifier.