Apparatuses and methods are disclosed for applying laser energy having desired pulse characteristics, including a sufficiently short duration and/or a sufficiently high energy for the photomechanical treatment of skin pigmentations and pigmented lesions, both naturally-occurring (e.g., birthmarks), as well as artificial (e.g., tattoos). The laser energy may be generated with an apparatus having a resonator with the capability of switching between a modelocked pulse operating mode and an amplification operating mode. The operating modes are carried out through the application of a time-dependent bias voltage, having waveforms as described herein, to an electro-optical device positioned along the optical axis of the resonator.

A semiconductor-laser-device assembly includes a mode-locked semiconductor-laser-element assembly including a mode-locked semiconductor laser element, and a dispersion compensation optical system, on which laser light emitted from the mode-locked semiconductor laser element is incident and from which the laser light is emitted; and a semiconductor optical amplifier having a layered structure body including a group III-V nitride-based semiconductor layer, the semiconductor optical amplifier configured to amplify the laser light emitted from the mode-locked semiconductor-laser-element assembly.

An optoelectronic oscillator for generating an optical and/or electric pulse comb, comprising a monolithically integrated passively mode-coupled semiconductor laser and an optical feedback loop which guides a part of the optical radiation of the semiconductor laser and feeds said part back into the semiconductor laser as feedback pulses. Without the influence of the feedback pulses, the semiconductor laser would emit comb-like optical pulses, hereafter referred to as primary pulses, and in the event of an influence, emits comb-like output pulses which have been influenced by the feedback pulses, said output pulses having a lower temporal jitter or less phase noise than the primary pulses. The feedback loop is damped between 27.5 and 37.5 dB, and the time lag of the feedback loop is selected such that each feedback pulse is incident within the temporal half-value width of each subsequent primary pulse.

A method for generating a single-cavity dualcomb or multicomb for laser spectroscopy, the method comprising the steps of providing a laser system comprising a pump source, a gain medium, and a resonator having a spectral filter; spectrally filtering, by the spectral filter, light in the resonator and attenuating, in particular blocking, by the spectral filter, one or more wavelength bands at least one of which being located completely within the gain bandwidth of the laser system such that two or more at least partially separated spectral regions are provided; mode-locking the two or more at least partially separated spectral regions.

A pulse laser apparatus (100) for creating laser pulses (1), in particular soliton laser pulses (1), based on Kerr lens mode locking of a circulating light field in an oscillator cavity (10), comprises at least two resonator mirrors (11, 12, . . . ) spanning a resonator beam path (2) of the oscillator cavity (10), at least one Kerr-medium (21, 22, 23) for introducing self-phase modulation and self-focusing to the circulating light field in the oscillator cavity (10), at least one gain-medium (31) for amplifying the circulating light field in the oscillator cavity (10), and a tuning device (40) for setting a first mode-locking condition and a second mode-locking condition of the oscillator cavity (10) such that an intra-cavity threshold-power for mode-locking at the first mode-locking condition is lower than that at the second mode-locking condition, wherein the first mode-locking condition is adapted for starting or shutting-down of the Kerr lens mode locking and the second mode-locking condition is adapted for continuous Kerr lens mode locking and a resonator-internal peak-power of the circulating light field is higher at the second mode-locking condition than at the first mode-locking condition. Furthermore, a method of operating a pulse laser apparatus is described.

A laser includes a traveling wave laser cavity with an active section, a pulse stretcher, and a pulse compressor. The pulse stretcher is coupled to the waveguide before the active section and the pulse compressor is coupled to the waveguide after the active section.

A series of laser pulse bundles or bursts are used for micromachining target structures. Each burst includes short laser pulses with temporal pulse widths that are less than approximately 1 nanosecond. A laser micromachining method includes generating a burst of laser pulses and adjusting an envelope of the burst of laser pulses for processing target locations. The method includes adjusting the burst envelope by selectively adjusting one or more first laser pulses within the burst to a first amplitude based on processing characteristics of a first feature at a target location, and selectively adjusting one or more second laser pulses within the burst to a second amplitude based on processing characteristics of a second feature at the target location. The method further includes directing the amplitude adjusted burst of laser pulses to the target location.

The present disclosure provides a method of optimising an optical system of a mode-locked laser oscillator or a regenerative, multi-pass or single pass amplifier. The method may include the steps of identifying crystallographic axes of an active laser gain medium crystal, cutting the crystal, and orienting the crystal in the optical system in a predetermined orientation relative to a propagation vector of a laser pulse depending on the required output of the optical system.

Disclosed herein is a single pulse laser apparatus which includes a first mirror and a second mirror disposed at both ends of the single pulse laser apparatus and having reflectivities of a predetermined level or more; a gain medium rotated at a predetermined angle and configured to oscillate a laser beam in a manual mode-locking state; a linear polarizer configured to output a beam having a specific polarized component of the oscillated laser beam; an etalon configured to adjust a pulse width of the oscillated laser beam; and an electro-optic modulator configured to perform Q-switching and single pulse switching.

A surface-emitting semiconductor laser system contains at least one MQW unit of at least three constituent QWs, axially separated from one another substantially non-equidistantly. The MQW unit is located within the axial extent covered, in operation of the laser, by a half-cycle of the standing wave of the field at a wavelength within the gain spectrum of the gain medium; immediately neighboring nodes of the standing wave are on opposite sides of the MQW unit. So-configured MQW unit can be repeated multiple times and/or complemented with individual QWs disposed outside of the half-cycle of the standing wave with which such MQW unit is associated. The semiconductor laser further includes a pump source configured to input energy in the semiconductor gain medium and a mode-locking element to initiate mode-locking.